feat: AI commit messages, change tree, router behavesAs, sidebar times (v2.2.0)

- Changes panel: Files and Changes merged into one panel; the overview's
  groups drawn as a folder tree (compacted chains, file counts, fold,
  stage/unstage a whole folder)
- AI-suggested commit message for what is staged
  (POST /api/lanes/:id/git/commit-message, claude -p --safe-mode, haiku)
- AI Router: optional "Behaves as" Claude model id, written as
  modelPicker options into the router's --settings file (issue #56)
- Sidebar: session rows show last activity, live rows their start time;
  a closed Terminal row can be removed (DELETE /api/run/history/:id)
- Every pane's CLI starts only once a client is attached; claude panes
  no longer forced inline; tmux scrollbar one column wide
- Update notifier: "Check for updates" reopens a closed notice

docs/API.md

@@ -614,7 +614,7 @@ answer `{available:false}` with HTTP **200** for a cwd git cannot read.
   ignore (`ls-files --cached --others --exclude-standard`), directories folded
   and listed first. A changed file carries its porcelain `status` (` M`, `??`,
   `A `, ` D`…), a folder with anything changed under it `changed: true`. `400 EBADPATH` for a path that escapes the workspace.
-- **`/git/tree-all`** → `{available, levels: {"<dir>": [{name, path, dir}]}, truncated}` — every level of the same tree (entries decorated the same way) from ONE `git ls-files`, each level shaped and capped like `/git/tree`'s; the Files tab's **Expand all folders** is this one request instead of one per folder.
+- **`/git/tree-all`** → `{available, levels: {"<dir>": [{name, path, dir}]}, truncated}` — every level of the same tree (entries decorated the same way) from ONE `git ls-files`, each level shaped and capped like `/git/tree`'s; the Changes panel's Files mode's **Expand all folders** is this one request instead of one per folder.
 
 #### Read a workspace's own branches
 
@@ -655,6 +655,22 @@ reason is gone) is cleared first. A live pane still holding the session is
 `409 ELIVE`; no `confirm` is `400 ECONFIRM`; a session with no worktree here
 `400 ENOWORKTREE`. Answers `{removed: true, branch, branchKept}`.
 
+#### Suggest a commit message
+
+```http
+POST /api/lanes/:id/git/commit-message
+```
+
+The Changes panel's ✨ button beside the commit box. Runs the user's own
+`claude` CLI — `claude -p --safe-mode --no-session-persistence --tools "" --model haiku`
+— on the **staged** diff of the workspace's cwd (or `?session=` worktree), sent on
+stdin together with the last ten commit subjects so the message follows the
+repo's style. Only reads: no tool, hook or plugin runs, no transcript is saved,
+and a `settings.local.json` is never part of the diff. Same-origin, because
+each call spends the user's Claude quota. Answers `{"message": "..."}`;
+`400 ENOSTAGED` with nothing staged, `400 ENOTOOL` without `claude` on PATH,
+`502 EAI` when the CLI fails, answers empty or runs past 120 s.
+
 #### Act on a workspace's working copy
 
 ```http
@@ -2369,7 +2385,7 @@ Each tool: `{ id, label, command, homepageUrl, installed, path, enabled, source:
 
 ```
 GET    /api/ai-routers                Every saved profile, the built-in `native` one first
-POST   /api/ai-routers                Create — Body: { label, baseUrl, apiKey?, model, models? }
+POST   /api/ai-routers                Create — Body: { label, baseUrl, apiKey?, model, models?, behavesAs? }
 POST   /api/ai-routers/test           Probe an endpoint — Body: { baseUrl, model, apiKey?, name? }
 PATCH  /api/ai-routers/:name          Update the same fields, all optional
 DELETE /api/ai-routers/:name          Delete one saved profile
@@ -2379,6 +2395,8 @@ A **router profile** is an endpoint that stands in front of Claude Code or Codex
 
 `models` carries the five per-tier names (`opus`, `sonnet`, `haiku`, `smallFast`, `subagent`). Any tier omitted is filled from `model`, so a router that answers to one symbolic name needs one field, not six.
 
+`behavesAs` (optional, `""` clears it, omitted on `PATCH` keeps it) is a Claude model id (`claude-…`, else `400 EBADMODEL`) that Claude Code should treat the router's own model names as. Without it, a name Claude Code's model catalog does not know — a 9Router combo such as `agent` — makes every session print "isn't described by this version's model catalog" and compact at an assumed 200k window (issue #56). The user picks it, never AgentHub: it also sets the context window Claude Code compacts at, and only the user knows which model the router really sends a name to.
+
 **No response here ever contains key material.** A saved profile reports `hasKey: true|false` and there is deliberately no `GET /:name` — a route returning one profile in full would be the single way an API key could leave the server. Profiles live one JSON file each under `<CLAUDE_HOME>/agenthub-routers/` (dir `0700`, files `0600`). An omitted `apiKey` on `PATCH` keeps the stored one; the edit form cannot display a key, so it has none to send back.
 
 **`POST /api/ai-routers/test`** answers the question saving cannot: does this endpoint, with this key, actually serve this model? It sends one Anthropic-style message capped at a single output token to `<baseUrl>/v1/messages` (a 15 s timeout), which is the wire shape a claude workspace's eight env keys point at — a Codex-only router is not covered. A router that answers is a `200` here whatever it replies: `{ ok, status, message }` carries the router's own words (truncated to 300 characters), and `status` is `null` when nothing answered at all. Only bad input is a 4xx.
@@ -2389,7 +2407,7 @@ The stored key is only ever sent to the endpoint it was stored against. A blank
 
 **Starting a session on a router.** `POST /api/lanes/:id/start` and `POST /api/run` take `router: "<name>"` (omitted, `""` or `"native"` = the vendor's own API). Only the name comes from the request; the key and endpoint come from the store. An unknown name is `400 EBADROUTER`, a router on a tool other than Claude/Codex `400 EUNSUPPORTED`. A resume (`resumeSessionId`, `resume`) that names no router goes back to the one its session last ran on (`dashboard_runs.router`), or native once that profile is deleted. Each spawn (re)writes the profile's files:
 
-- **Claude** gets `--settings=<data dir>/router-settings/<name>.json` (dir `0700`, file `0600`): an `env` block with the eight keys `ANTHROPIC_BASE_URL`, `ANTHROPIC_AUTH_TOKEN`, `ANTHROPIC_MODEL`, `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, `ANTHROPIC_DEFAULT_HAIKU_MODEL`, `ANTHROPIC_SMALL_FAST_MODEL`, `CLAUDE_CODE_SUBAGENT_MODEL` (an empty one left out). The command-line layer outranks the project-local and user settings, so two sessions of one workspace can run on two routers, and only the path is in argv. Native adds nothing, so a router the user set in their own `~/.claude/settings.json` still applies to a native session.
+- **Claude** gets `--settings=<data dir>/router-settings/<name>.json` (dir `0700`, file `0600`): an `env` block with the eight keys `ANTHROPIC_BASE_URL`, `ANTHROPIC_AUTH_TOKEN`, `ANTHROPIC_MODEL`, `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, `ANTHROPIC_DEFAULT_HAIKU_MODEL`, `ANTHROPIC_SMALL_FAST_MODEL`, `CLAUDE_CODE_SUBAGENT_MODEL` (an empty one left out), plus — only when the profile sets `behavesAs` — `modelPicker: { options: [{ model, behavesAs }] }` with one row per distinct model name that is not a bare `claude-*` id. Claude Code reads `modelPicker` from the policy, flag and user layers and takes the FIRST it finds, so while set it replaces a `modelPicker` in the user's own `~/.claude/settings.json` for that session (verified on 2.1.290). The command-line layer outranks the project-local and user settings, so two sessions of one workspace can run on two routers, and only the path is in argv. Native adds nothing, so a router the user set in their own `~/.claude/settings.json` still applies to a native session.
 - **Codex** gets `-p <name>` and `$CODEX_HOME/<name>.config.toml`, the layer that flag loads on top of the base config (never touched). The layer sets `wire_api = "responses"` (codex-cli 0.149 refuses `"chat"`); `env_key` is written only when the profile has a key, and the key reaches the pane as `AGENTHUB_ROUTER_KEY` through tmux's own `-e`, never as typed text.
 
 `PATCH` rewrites the profile's files that exist (a live Claude session reads its file again; the next Codex session gets the new layer) and `DELETE` removes both. Workspaces no longer carry a router: `POST /api/lanes/:id/router/apply` is gone, and at every start the server takes the eight keys an older build wrote into a workspace's `.claude/settings.local.json` back out and clears `lanes.router_profile` (a file that is not valid JSON is left alone and retried next start).

docs/LANES.md

@@ -396,7 +396,7 @@ The dashboard web UI merges workspaces and runs into a single **Workspace** page
 - **Right-click menus** — every item that has actions opens them on a right-click too, in one shell (`client/src/components/ContextMenu.tsx`: placed at the pointer, kept inside the viewport, closed by Escape, a click outside or an item). The buttons stay; the menu repeats what they do and nothing more. A session row — in the sidebar, the home's Recents and the archived fold (`lanes/SessionMenu.tsx`) — offers Open, Open in split (live), Rename and Archive (sidebar), Unarchive (archived), Session details, Copy session ID and Close tab (live); the sidebar's **New session** row Open, Open in split and Close tab. A console tab offers Open, Open in split, Session details, Copy session ID and Close tab; a pane header (split view) Show <session> here, Split right/down with a new terminal and Close pane. In the Changes panel a changed file (overview row or review header) offers Open, Stage/Unstage, Discard — two clicks, as on its trash button — or the conflict's Keep mine / Take theirs / Mark resolved, and Copy relative path; a Files tree entry Open and Copy relative path; a History commit View commit, Copy commit SHA and Copy commit message. The home's title opens the row menu, and a Context file or extra folder offers Copy path and Remove. Outside the workspace the same shell serves the Sessions table, the Dashboard's agent cards and recent events, the Activity feed and Workflow runs (`components/SessionRowMenu.tsx`: Open session details, Open in its workspace when it has one, Copy session ID, Copy folder path), an attached prompt image (View / Remove), the managed workspace card (Reset), every Settings list (Git credentials, AI Router, Pricing, alert rules, webhooks, remote sources, AI tools) and every Claude Code / Codex config list (skills, agents, commands, output styles and memory files via `FileItemMenu` in `components/config/MdItemList.tsx`; plugins, MCP servers, marketplaces, auth profiles). A delete or remove there takes the button's own confirm — a modal, or two clicks. Text areas (the terminal, a conversation, a diff) keep the browser's own menu. The shell stops the menu's clicks from reaching the card it was opened from.
 - **The workspace home** — `/workspace?lane=<id>` opens on the workspace's home (`client/src/components/lanes/WorkspaceHome.tsx`), shaped like a Claude Desktop project page: the name (rename from its `⋯` menu, which is the sidebar row menu) with the repository it belongs to under it (root, the main worktree's branch, the worktree count, from `GET /api/projects` — the facts Settings → Projects used to show), a prompt box — the one place a session starts WITH a prompt (a pane has no run form; the session view's tab bar `+` only starts a bare CLI or a shell) — whose fields run in order **AI** (the session's own tool: every installed, enabled one, the workspace's by default), **AI Router** (Native or a saved profile; Native alone, disabled, for a tool that cannot use one), **Model** (the tool's own list, or on a router that router's models), **Permission** (Claude's permission mode; Codex's sandbox and approval; a catalog tool's per-session bypass switch) and **Effort** (Claude and Codex), and whose **Start** opens a NEW session in the first slot with no live run (0–9, `POST /api/lanes/:id/start {slot}`; all ten busy is refused) and then shows it in a tab of its own, and **Recents** — the workspace's own sessions (`?lane=<id>`) with their cost and time, a live one opening its pane and any other its conversation (`&session=`), exactly like the sidebar. The transcript page (`/sessions/<id>`) of a Claude session started in a workspace's own folder carries an explicit **Resume** (`client/src/components/lanes/SessionResumeButton.tsx`, the one place that resumes) and beside it **Fork**, which resumes the history into a NEW session id (`{forkSession: true}` → `--fork-session`, the original untouched, offered even while the original has a live pane): it warns that a resume re-reads the whole transcript into context, re-reads the live panes, then starts it in the workspace's first free pane (`POST /api/lanes/:id/start {slot, resumeSessionId}`) and opens it. A session from a SUBFOLDER gets no Resume — the pane starts in the workspace's folder and Claude finds a session by the folder it ran in — and a session that still has a live pane shows **Open pane** instead. On the right sit the workspace's own context: **Instructions** (appended to every new session's system prompt), **Memory** (read-only: the folder's CLAUDE.md / AGENTS.md family and Claude's auto memory), **Context** (uploaded files, ≤ 10 MB each, stored by AgentHub) and **Folder** (the workspace's own folder plus extra ones, with the repo's untracked worktrees suggested). Only Claude and Codex panes can take them (`--add-dir`, `--append-system-prompt-file=` / `-c developer_instructions=`); for any other tool the page says so and its panes start without them. See `docs/API.md` → Workspace context. The home HIDES the session view with CSS — the console never unmounts behind it.
 - **A session in its own worktree** — Claude Desktop's worktree toggle: the row under the home's prompt box has a **Local / New worktree** select (Claude workspaces in a git repo). Claude Code itself makes a worktree only when started with `--worktree` or when asked mid-session — and a worktree it enters mid-session is invisible to AgentHub, which reads a session's folder once, at its start, and the new session's pane runs `claude --worktree=<name>`, so CLAUDE CODE makes `<repo>/.claude/worktrees/<name>` on branch `worktree-<name>`, copies `.worktreeinclude`, runs your `WorktreeCreate` hook, and on exit removes a worktree with no changes (or asks). AgentHub adds `/.claude/worktrees/` to the repo's `info/exclude` (Claude does not, and the main repo would list it). The session stays this workspace's own — listed with a branch icon and the worktree's name — and the session view's Changes panel works in ITS worktree (every git route with `?session=`, resolved from the session row: owned by the workspace, registered by `git worktree list`; `ENOWORKTREE` otherwise, never the main folder). Resume and Fork start in that worktree. **Archive** of a worktree session with no live pane asks first and removes the worktree like Claude Desktop — `git worktree remove` without force (git refuses unsaved work, and then nothing is archived) and `git branch -d` (unmerged work keeps its branch); a lock held by a live process refuses, a stale one is cleared. The workspace's own folder is never removed.
-- **The session view** — `/workspace?lane=<id>&run=<runId>` (a live session picked in the sidebar or Recents, or one just started) shows the console's tabs and the Files / Changes panel, with that run's tab active. The sidebar's workspace row always opens the workspace's home, live tabs or not (a live tab opens from its session row); the **Home** button at the left end of the tab bar opens the home of a workspace whose tabs stay running. Every workspace keeps its own tabs, panes and sessions: another workspace's tab is never shown. A browser notification for a workspace with a live pane opens it here directly.
+- **The session view** — `/workspace?lane=<id>&run=<runId>` (a live session picked in the sidebar or Recents, or one just started) shows the console's tabs and the Changes panel, with that run's tab active. The sidebar's workspace row always opens the workspace's home, live tabs or not (a live tab opens from its session row); the **Home** button at the left end of the tab bar opens the home of a workspace whose tabs stay running. Every workspace keeps its own tabs, panes and sessions: another workspace's tab is never shown. A browser notification for a workspace with a live pane opens it here directly.
 - **Untracked worktrees** are no longer listed in the sidebar; Settings → Git → **Worktrees** (`showUntracked`, hidden sources `claude` = `<repo>/.claude/worktrees/*` and `agenthub` = `LANES_ROOT`) now decides which of them the home's Add folder suggests.
 - **No workspaces yet** — the page shows a single banner (`lane-empty`): icon, one line of what a workspace is, the CLI equivalent (`agenthub workspace add --cwd $(pwd)`) and an **Add workspace** affordance. The whole banner IS the button — clicking anywhere on it opens the Add-workspace modal. The banner stays compact on purpose: the run setup form below it is what needs the height.
 - **Reordering** — drag a row and drop it anywhere in the list (a line shows where it lands, by the pointer's position — on another row, on a session list, above the first or below the last), or press **Alt+↑/↓** with a row focused. The order is a **per-viewer preference**, not a workspace fact: it persists to `localStorage` (`agenthub.workspace.laneOrder`) and writes nothing server-side — `GET /api/lanes` and `agenthub workspaces` keep answering in id order, and the order does not follow you to another browser. A workspace the stored order has never seen lands at the END; a stored id whose workspace is gone is skipped.
@@ -406,7 +406,7 @@ The dashboard web UI merges workspaces and runs into a single **Workspace** page
 - **Terminal** — a real interactive terminal (xterm.js) displaying the tmux session's PTY output, with full support for interactive commands, editors, and pagers. A live run keeps its rendered history and scroll position when scrolling. It grabs the keyboard the moment it appears, so typing goes into the pane without clicking it first. A pane has **no run form of its own**: a session with a prompt starts from the workspace home's prompt box. There is no **New run** button: when a pane's process ends (a double Ctrl+C out of `claude`, `exit`, a crash) its pane closes; the last one shows the next open tab, or the home when none is left. A pane with nothing to show offers **New session**, which opens the home too.
   Keyboard: the terminal keeps Tab and Shift+Tab (`claude` cycles its permission mode on Shift+Tab), so **Ctrl+M** toggles *Tab moves focus* — VS Code's way out of its terminal — and Tab then leaves the pane; **Cmd+F** (macOS) / **Ctrl+Shift+F** opens a find bar. URLs open in a new tab; a selection tmux copies (OSC 52) lands in the browser clipboard, and that path is write-only — nothing in the pane can read your clipboard. `agenthub.terminal.screenReader` = `"1"` in `localStorage` turns on xterm's screen-reader mode. While the socket is down a **Reconnecting…** overlay says keystrokes are not reaching the pane; it re-attaches by itself. In the session view, outside a terminal or a text field, `Alt+1`–`Alt+4` focuses pane 1–4, `Alt+\` splits the focused pane right with a new terminal, and `Alt+W` closes the focused pane (its session stays a tab).
 - **Clipboard in a pane** — the workspace's tmux session is started with the graphical session's own `DISPLAY`/`WAYLAND_DISPLAY`/`XAUTHORITY`/`XDG_RUNTIME_DIR` (read from `systemctl --user show-environment`, this process's own values winning; `server/lib/desktop-env.js`). The dashboard normally runs as a systemd *user* service, which has none of them, so a pane it started had no clipboard at all and `claude` answered "no image found in clipboard" on every image paste while the same CLI pasted fine in a terminal. Only those four names are forwarded, and only into panes this dashboard spawns — an already-running pane keeps the environment it was started with, so it needs a restart to gain one.
-- **Scrollbar in a pane** — every pane gets tmux's `mouse on` and `pane-scrollbars on` with a visible style (`pane-scrollbars-style fg=brightwhite,bg=black,width=2`, `enableMouse` in `server/lib/tmux.js`; tmux 3.7+). tmux keeps no history and draws no scrollbar on the alternate screen, so a `claude` pane is started with `CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1` (`spawnRun` in `server/lib/pty-run.js`) and renders inline even when `~/.claude/settings.json` says `"tui": "fullscreen"`. That setting still applies to `claude` in your own terminals; a pane started before this change keeps fullscreen until it is restarted.
+- **Scrollbar in a pane** — every pane gets tmux's `mouse on` and `pane-scrollbars on` with a visible style (`pane-scrollbars-style fg=brightwhite,bg=black,width=1`, `enableMouse` in `server/lib/tmux.js`; tmux 3.7+ — one column, since tmux 3.7c reserves `width` columns but paints only the first and a wider bar left a column of stale cells that read as a second scrollbar). tmux keeps no history and draws no scrollbar on the alternate screen, so a `claude` pane under `"tui": "fullscreen"` (`~/.claude/settings.json`) scrolls inside Claude's own UI instead. AgentHub no longer forces it inline (`CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1`): inline, every time the pane narrowed tmux re-wrapped Claude's full-width rules and pushed lines into history that its redraw could not clear, duplicating the banner and transcript. A pane started before this change keeps inline mode until it is restarted. Every pane's CLI (and a Terminal tab's shell) also starts only once a client is attached — 2 s at most — so nothing is drawn at tmux's 80×24 birth size and re-wrapped on the attach (`WAIT_FOR_CLIENT` in `server/lib/pty-run.js`, issue #55).
 - **Tabs** — the session view's console is a tab bar (`client/src/components/run/ConsoleTabs.tsx`) over the workspace's live tmux sessions — at most ten, its slots 0–9: slot 0 is the workspace's `agenthub-lane-<id>` (its `run_id`), slots 1–9 are `agenthub-lane-<id>-<slot>`. Every tab is a **combo**: a group of one to four split panes, each session in exactly one tab (`PaneGroups` in `client/src/lib/paneLayout.ts`). A one-pane tab shows its AI tool's icon and name (or **Terminal**); a combo tab shows every pane's icon and name, and the most urgent state dot. The active tab is the one on screen and its focused pane is the URL's `?run=`, so the Changes panel and Analyst follow it. A click shows a tab; **Ctrl/Cmd+click** on a one-pane tab or a `+` item brings it into the tab on screen, split to the right (a full tab — four panes — opens it as a tab of its own instead), and a one-pane tab dragged onto a pane joins that tab there. Any tab drags along the bar to reorder it; a pane's header dragged onto the bar takes that pane out into a tab of its own at that place. Every live session stays mounted and those of other tabs are hidden with CSS, so switching tabs never drops a terminal. A tab's **×** stops every session in it (`DELETE /api/run/<runId>`, after a confirm when one is an AI tool); with no tab left it moves to the home. The **+** menu opens a new tab in the first free slot, which the server picks (`slot: "auto"`, under the workspace lock): **New terminal** (your own default shell in the workspace folder — `POST /api/lanes/:id/start {slot, shell: true}`, recorded as tool `shell`; it is not an agent, so the workspace's `run_id`/`status` are left alone), each installed, enabled AI tool (started bare, on its default model, no prompt), and **Agent settings…** (Settings → Agents). With ten sessions open **+** is disabled. EVERY tab is bound to the sidebar's selection. A tab has no header of its own (no title, no **Active runs** list, no **New run**): other sessions are opened from the sidebar or the home's Recents. (The old fixed 1/2/4 split layout and its `agenthub.workspace.splitView` key are gone; **Split panes** replaces them.)
 
 - **Split panes** — the console splits like VS Code (`client/src/components/run/PaneGrid.tsx`, model in `client/src/lib/paneLayout.ts`): one binary tree of splits PER TAB, each side by side or stacked at a ratio, whose leaves are the workspace's slots — at most four panes in a tab, a session never shown twice. **Ctrl/Cmd+click** a one-pane tab, a `+` item or a sidebar session row brings it into the tab on screen, to the right of the focused pane (the intent rides on the navigation's state, never in the URL); with more than one pane each gets a slim header: **drag** it (or a tab) onto another pane — its edge splits there, its middle swaps the two —, its **▾** shows another live session in it (swapping with the pane that showed it), **Split right / Split down** puts a not-shown session or a **New terminal** beside it, and **×** takes the pane out of this tab into a tab of its own (its session keeps running). A session dropped or swapped in from another tab leaves that tab. Dividers drag (or move by arrow keys) between 10% and 90%. Clicking in (or tabbing into) a pane focuses it, `?run=` follows — so the right panel, Analyst and the sidebar read the focused session — and the keyboard goes with it: only the focused pane's terminal takes it when it appears. A pane closes when its terminal reports that its session ended (exited, closed from another browser); the run list itself only prunes a remembered layout on a workspace's first read, and a pane opened here whose session never got listed — one empty read, which the server returns on any tmux error, never wipes a split. A session ending while the home or a replay is shown only closes its pane; the URL stays. The tabs and their layouts are a viewer preference kept per workspace in `localStorage` (`agenthub.workspace.paneLayout`, `{groups, active}`; a stored pre-tab single layout reads as one tab), never on the server. Every pane is an absolutely placed sibling keyed by its slot, so splitting, swapping or resizing never re-parents — and so never remounts — a live terminal; the session view itself fills the page edge to edge, its tab bar and the right panel's activity bar one header strip.
@@ -610,13 +610,11 @@ which one is "work" changes several times an hour, so the width is a step, not
 a setting — and one button beats a width button wedged beside a collapse button
 in the panel's tightest corner. It is icon-only, and the icon it draws is the
 width the next click LANDS on (even split → wider → closed), with the wording
-left to its tooltip. Beside it, along the panel's top edge, an **activity bar**
-of two icon buttons picks what the panel shows (`agenthub.workspace.panelTab`):
-**Files** (the browse mode below, on its own — no git header, no mode
-switcher) and **Changes** (the git header and the other four modes). The
-workspace's sessions live in the sidebar and on its home only — the panel's
-former Sessions tab was a third copy of the same list. At Full screen the Files and Changes tabs show the same thing: the
-explorer sidebar beside the changes. It
+left to its tooltip. Files and Changes are ONE panel: its mode switcher reads
+**Changes** (the overview, where it opens) · **Files** · **Review** · **History**
+(the former activity-bar tabs and `agenthub.workspace.panelTab` are gone). The
+workspace's sessions live in the sidebar and on its home only. At Full screen
+Files is the explorer sidebar beside the changes, so its button is dropped. It
 reads the workspace's git surface in five modes:
 
 - **Files** — quick-open by path (`/git/ls`) or the repo's tracked file tree
@@ -719,7 +717,12 @@ refuses it without `confirm: true` and accepts only paths `git status` is
 already reporting as changed. In the `work` range the overview splits like VS
 Code's Source Control: **Staged Changes** (what the next commit takes, each row
 offering Unstage) above **Changes** (unstaged and untracked, each offering
-Stage); a partly staged file appears in both. In the tree, a changed file's
+Stage); a partly staged file appears in both. Each group is a folder tree like
+JetBrains' commit view (`client/src/lib/changeTree.ts`): folders first, a
+chain of folders holding only one sub-folder compacted into one row
+(`src/lib`), each folder row showing its file count, folding on a click and —
+in Staged Changes / Changes — carrying one button that unstages / stages every
+file under it; the group headers fold too. The fold state is not stored. In the tree, a changed file's
 whole row takes its status tint, not only its letter.
 
 Review, single-file, history and browse do **not** poll: re-fetching under the