feat(ui): AI Tools modal, one-button lane tool picker, AgentHub settings in Overview, markdown preview

- AI Tools moves from a Settings section into a modal behind a button at the
  Settings tab bar's right edge (AiToolsModal, `actions` on PageTabs,
  /settings#ai-tools); rows get an enable switch, Default badge, and an
  Update button for every tool whose catalog names an updater (no version
  lookup on open); not-installed tools fold behind a disclosure, a finished
  job's log folds to one line; shared AiToolIcon
- codex updates through its own `codex update`, openclaw/hermes gain
  `update --yes`; update-all runs every installed updater and skips an npm
  one only when npm does not manage the binary
- Add-lane tool picker is one button showing the chosen tool that opens the
  enabled tools as buttons
- Claude Code / Codex AgentHub sub-tab folded into Overview (home editor,
  hooks, pricing); the path list drops CLAUDE_HOME/CODEX_HOME;
  HomeDirSetting shows the saved value only while the field differs
- Preview/Raw toggle for markdown files in the config FileViewer and the
  Changes panel's whole-file view (MarkdownPreview: react-markdown +
  remark-gfm, raw HTML never run, frontmatter as a code block)
- docs and the CLAUDE.md marker updated

docs/DATABASE.md

@@ -66,7 +66,7 @@ graph TB
 **Database Location:**
 - **Canonical (default):** `~/.claude/agenthub/dashboard.db` — shared by `npm start`, `npm run dev`, and the desktop app when it uses the same data dir
 - **Override:** set `DASHBOARD_DATA_DIR` (directory) or `DASHBOARD_DB_PATH` (file path) for tests or custom deployments
-- **Pinned on a CLAUDE_HOME change:** the data dir defaults to `<CLAUDE_HOME>/agenthub`, so saving a new CLAUDE_HOME from Settings → Claude Code → AgentHub first writes the data dir in use as `DASHBOARD_DATA_DIR` to AgentHub's settings file (`~/.config/agenthub/settings.env`, or `$XDG_CONFIG_HOME/agenthub/settings.env`, or `AGENTHUB_SETTINGS_FILE`). The next start keeps the same database instead of opening an empty one under the new home. An explicit `DASHBOARD_DATA_DIR` is left alone
+- **Pinned on a CLAUDE_HOME change:** the data dir defaults to `<CLAUDE_HOME>/agenthub`, so saving a new CLAUDE_HOME from Settings → Claude Code → Overview first writes the data dir in use as `DASHBOARD_DATA_DIR` to AgentHub's settings file (`~/.config/agenthub/settings.env`, or `$XDG_CONFIG_HOME/agenthub/settings.env`, or `AGENTHUB_SETTINGS_FILE`). The next start keeps the same database instead of opening an empty one under the new home. An explicit `DASHBOARD_DATA_DIR` is left alone
 - **Legacy:** repo-local `./data/dashboard.db` is migrated into the canonical location on first launch (see `server/db.js`)
 - **Pre-rebrand:** an install that predates AgentHub keeps its data in `~/.claude/agent-dashboard/`. Server startup renames that directory to `~/.claude/agenthub/` once, before anything opens the database (`migrateLegacyDataDir()` in `server/lib/claude-home.js`). It is a same-filesystem rename, so it is instant even at multiple gigabytes and never leaves two copies. If the rename fails, or `DASHBOARD_DATA_DIR` is set, nothing moves and the old directory keeps being used.
 

docs/I18N.md

@@ -201,7 +201,7 @@ Formatting utilities are centralized in `client/src/lib/format.ts`.
 `formatTime`, `formatDateTime`, and `fmtCostFull` use locale-aware `toLocale*` APIs.  
 Timestamp parsing normalizes timezone-less SQLite datetime strings to UTC before display formatting.
 
-`formatModelName` converts raw model identifiers (e.g. `claude-opus-4-7-20260101`, `claude-opus-4-7[1m]`) into human-friendly display names (e.g. "Claude Opus 4.7", "Claude Opus 4.7 (1M)"). This is locale-independent (brand names are proper nouns) and is applied across all UI surfaces except the Model Pricing table (Settings → Claude Code → AgentHub, Settings → Codex → AgentHub and Settings → Antigravity), which shows raw patterns for pricing rule configuration.
+`formatModelName` converts raw model identifiers (e.g. `claude-opus-4-7-20260101`, `claude-opus-4-7[1m]`) into human-friendly display names (e.g. "Claude Opus 4.7", "Claude Opus 4.7 (1M)"). This is locale-independent (brand names are proper nouns) and is applied across all UI surfaces except the Model Pricing table (Settings → Claude Code → Overview, Settings → Codex → Overview and Settings → Antigravity), which shows raw patterns for pricing rule configuration.
 
 ```mermaid
 flowchart LR

docs/LANES.md

@@ -1113,7 +1113,7 @@ on every hook, live — so it only ever sees `claude` lanes.
 touches a `codex` lane sharing the same directory, nor a Codex hook the
 `claude` one — and runs detection for `claude` lanes only. Codex lanes carry no
 pipeline, so nothing detects or advances their stage. Codex's own hooks are
-opt-in (Settings → Codex → AgentHub → **Codex hooks**; Codex then asks you to
+opt-in (Settings → Codex → Overview → **Codex hooks**; Codex then asks you to
 trust them): with them a codex lane gets `running`/`idle` as each turn starts
 and ends, and "Codex needs your permission: …" as its `needs_action` while
 Codex waits on an approval. A sub-agent thread's tool calls are folded onto
@@ -1128,7 +1128,7 @@ start and end): every `DASHBOARD_CODEX_POLL_MS` (default 15000; `0`
 disables) it lists `$CODEX_HOME/sessions/<YYYY>/<MM>/<DD>/rollout-*.jsonl`
 (`$CODEX_HOME` defaults to `~/.codex`; every codex pane is started with the
 dashboard's own `CODEX_HOME` through tmux `-e`, so the pane writes where this
-reads; it is editable in Settings → Codex → AgentHub, and a save re-writes each
+reads; it is editable in Settings → Codex → Overview, and a save re-writes each
 codex lane's AI Router layer into the new home — a pane already running keeps
 the old one until it restarts), reads each thread's `cwd` from the
 `session_meta` on the file's first line, and calls the owning lane `running`
@@ -1703,7 +1703,7 @@ agenthub stage <stage> [--evidence "..."]         # Report the current stage
 
 ## Lanes on any AI tool
 
-A lane can run any AI coding CLI in the AI Tools catalog (`server/data/ai-tools/*.json`, plus any `*.json` in `DASHBOARD_AI_TOOLS_DIR`, which replaces a built-in file with the same `id` but may not set `launcher`). Settings → Dashboard → **AI Tools** lists what is installed (found on PATH; **Refresh** re-reads the login shell's PATH first) with **Enabled/Disabled** and **Set default**, and what is available to install with a homepage link. The Add-lane modal offers **Default (<tool>)** and **Other…**; `agenthub lanes add --tool <id>` does the same from a terminal.
+A lane can run any AI coding CLI in the AI Tools catalog (`server/data/ai-tools/*.json`, plus any `*.json` in `DASHBOARD_AI_TOOLS_DIR`, which replaces a built-in file with the same `id` but may not set `launcher`). The **AI Tools** button at the right of the Settings tab bar opens a dialog (also `/settings#ai-tools`) that lists what is installed (found on PATH; **Refresh** re-reads the login shell's PATH first) with an enable switch, **Set default** and **Update** (for every tool whose catalog file names an updater — no version lookup, the updater itself reports "up to date"), and, folded behind a disclosure, what is available to install with a homepage link. The Add-lane modal shows the chosen tool as one button (the default until changed); clicking it lists every installed, enabled tool as buttons to pick from; `agenthub lanes add --tool <id>` does the same from a terminal.
 
 A catalog file: