feat(lanes): reorder and rename lane cards, and show each file's line delta

The lane strip's tiles are now drag-reorderable (Alt+←/→ is the keyboard
path), and a lane's name can be set in place from the detail header. The
"Lane 23 ·" prefix is gone from both — the bare `#23` stays on the tile,
because that number is how the CLI addresses a lane.

Card order is a per-viewer preference, not a lane fact: it lives in
localStorage (`agenthub.workspace.laneOrder`) beside the split-view layout
and writes nothing server-side, so `GET /api/lanes` and `agenthub lanes`
keep answering in id order. Renaming is the opposite — it is PATCH
/api/lanes/:id with {title}, the one lane column a user now types into
directly.

That made a patch value reachable by hand for the first time, so
`bindable` now rejects any non-scalar for every PATCHABLE column with
EBADFIELD, and the route answers 400 for that and for the
SQLITE_CONSTRAINT family, rather than handing better-sqlite3 a datatype
throw and reporting 500 on plain bad input.

The uncommitted-files tooltip became a real panel. `GET /api/lanes/:id/git`
now returns `files` as {path, status, added, deleted} records — deltas from
one `git diff --numstat HEAD`, null where git has none to report (untracked,
binary, renamed) — and the card renders them portalled to the body, so the
Workspace's own scroll box cannot clip the list.

docs/LANES.md

@@ -371,8 +371,10 @@ A missing source `.env` falls back to `.env.example` with a loud warning, never
 The dashboard web UI merges lanes and runs into a single **Workspace** page accessible at `/run` (the old `/lanes` route now redirects here). Top to bottom:
 
 - **No page header.** The page title and the four counters (`lanes`, `running`, `needs you`, `dead`) are gone: the lane strip below already shows every lane with its own liveness dot and its ⚠ marker, so the counters restated it a row higher and cost height on a screen whose point is the terminal. `GET /api/lanes` still returns `counts` for other callers.
-- **Lane strip** — the horizontally scrolling row of lane tiles. Its FIRST tile is **Add lane** (dashed border, no liveness dot), not a header button: creating a lane is the same kind of act as picking one, so it reads as the empty slot at the head of the row.
-- **Lane-detail header row** — one row, and every per-lane control lives on it: liveness + status, the lane's name, time-on-stage, the pipeline picker, the Model (AI Router) select, stage badges, the feature picker, and on the right the **Tools** menu (agents install / mcp sync / sync-base check, hidden when the lane declares no runtime profile), the info toggle, the split-view toggle and Remove. Tools sits here rather than in Settings because all three of its actions run against one lane's `cwd` — in Settings it would need a lane picker just to say which.
+- **Lane strip** — the horizontally scrolling row of lane tiles. Its FIRST tile is **Add lane** (dashed border, no liveness dot), not a header button: creating a lane is the same kind of act as picking one, so it reads as the empty slot at the head of the row. A tile shows the lane's id as a bare `#23` — not "Lane 23", which cost a third of the row's width and said nothing, though the number itself stays because that is how the CLI addresses a lane.
+- **Reordering the strip** — drag a tile onto another to move it there, or press **Alt+←/→** with a tile focused (the keyboard path; HTML5 drag-and-drop has no touch support and does not auto-scroll an overflowing strip). The order is a **per-viewer preference**, not a lane fact: it persists to `localStorage` (`agenthub.workspace.laneOrder`) exactly like the split-view layout beside it, and writes nothing server-side — `GET /api/lanes` and `agenthub lanes` keep answering in id order, and the order does not follow you to another browser. A lane the stored order has never seen (created since, or created in another tab) lands at the END rather than wherever a stale index would put it; a stored id whose lane is gone is skipped.
+- **Renaming a lane** — the detail header's name is a button: click it (a pencil appears on hover) to edit in place. **Enter** saves via `PATCH /api/lanes/:id` with `{title}`, **Escape** and clicking away both cancel, and saving an empty name clears the title, which puts the lane's `cwd` back in its place. Renaming is display-only — a managed lane's branch name was slugified from its title once, at creation.
+- **Lane-detail header row** — one row, and every per-lane control lives on it: liveness + status, the lane's name (no "Lane 23 ·" prefix — the id is on the strip tile), time-on-stage, the pipeline picker, the Model (AI Router) select, stage badges, the feature picker, and on the right the **Tools** menu (agents install / mcp sync / sync-base check, hidden when the lane declares no runtime profile), the info toggle, the split-view toggle and Remove. Tools sits here rather than in Settings because all three of its actions run against one lane's `cwd` — in Settings it would need a lane picker just to say which.
 - **Detail panel** — the selected lane's declared stage, its inferred stage when detection leads, a full-width pipeline map, and a legend naming all five node states plus the dashed-amber inferred treatment.
 - **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.
 - **Split view** — a layout toggle (one pane / two side by side / a 2×2 grid, drawn as icons rather than the words, with the count kept as each button's `aria-label` and tooltip) renders that many independent terminal panes side by side (`grid-cols-2` for 2, a 2×2 grid for 4). Layout 1 is bound to the lane strip's selection, same as always; layouts 2 and 4 give each pane its own lane picker, independent of the strip. The chosen layout and each pane's lane persist to `localStorage` (`agenthub.workspace.splitView`) across reloads.
@@ -445,7 +447,11 @@ curl http://localhost:4820/api/lanes/5/git
   "subject": "free-text rule mode in the form",
   "dirty": 2,
   "untracked": 1,
-  "files": [" M server/lib/alerts.js", " M client/src/lib/api.ts", "?? scratch.txt"]
+  "files": [
+    { "path": "server/lib/alerts.js", "status": " M", "added": 12, "deleted": 3 },
+    { "path": "client/src/lib/api.ts", "status": "M ", "added": 1, "deleted": 0 },
+    { "path": "scratch.txt", "status": "??", "added": null, "deleted": null }
+  ]
 }
 ```
 
@@ -454,15 +460,26 @@ curl http://localhost:4820/api/lanes/5/git
   is a normal state, not a fault, and the card simply renders without a git row.
 - A detached checkout reports the literal `HEAD` that git returns, rather than a
   prettier invention.
-- `files` holds the raw `git status --porcelain` lines the two counts came from,
-  **capped at 20** — the card hovers them as a tooltip on the
-  `N modified · N untracked` text, and a lane mid-`npm install` would otherwise
-  ship thousands of paths through a polled endpoint. The counts are never
-  capped, so the tooltip appends `… +N` when it is showing less than all of it.
+- `files` names the files the two counts came from, **capped at 20** — a lane
+  mid-`npm install` would otherwise ship thousands of paths through a polled
+  endpoint. The counts are never capped, so the panel that shows this list says
+  `… and N more files` when it is showing less than all of it. Each entry
+  carries its two-character `git status --porcelain` code (`status`, for a
+  rename the `path` is the NEW one) and its line delta.
+- `added`/`deleted` come from one `git diff --numstat HEAD`, which covers staged
+  and unstaged work together. They are `null` when git has no delta to report:
+  an **untracked** file (git has never seen it — its content is deliberately not
+  read off disk, since a lane mid-build can have a 100 MB artifact), a **binary**
+  file, a **rename** (numstat keys those differently), or a repo with no commit
+  to diff against yet.
+- Hovering (or focusing, or tapping) the `N modified · N untracked` text on a
+  lane card opens this list as a panel: one row per file, its status letter
+  colour-coded, the directory truncated before the filename ever is, and each
+  row's `+N −M` aligned on the right under a total.
 - An unknown lane id is a `404`.
 
 This is **not** folded into `GET /api/lanes` on purpose: it shells out to git
-three times, and the lane list is polled and re-broadcast on every hook-driven
+five times, and the lane list is polled and re-broadcast on every hook-driven
 `lane_update`. Putting it there would fire a burst of subprocesses behind every
 tool call an agent makes. The browser fetches it per card instead, on mount and
 every 30 seconds, and a failed fetch is silent.