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.

server/openapi-extra/lanes.js

@@ -268,13 +268,13 @@ const paths = {
       tags: ["Lanes"],
       summary: "A lane's working-copy facts",
       description:
-        "Branch, short HEAD, that commit's subject, and the uncommitted counts for the lane's cwd. Read-only, so no same-origin guard. Kept out of GET /api/lanes because it shells out to git three times and that payload is polled and re-broadcast on every lane_update. A cwd that is missing, is not a git repository, or makes git fail returns available:false with HTTP 200 — a lane pointing at a plain directory is a normal state, not a fault.",
+        "Branch, short HEAD, that commit's subject, and the uncommitted counts for the lane's cwd. Read-only, so no same-origin guard. Kept out of GET /api/lanes because it shells out to git five times and that payload is polled and re-broadcast on every lane_update. A cwd that is missing, is not a git repository, or makes git fail returns available:false with HTTP 200 — a lane pointing at a plain directory is a normal state, not a fault.",
       operationId: "getLaneGitFacts",
       parameters: [{ name: "id", in: "path", required: true, schema: { type: "integer" } }],
       responses: {
         200: {
           description:
-            "available:true with {branch, head, subject, dirty, untracked, files}, or available:false alone. files holds the raw `git status --porcelain` lines behind those counts, capped at 20; the counts themselves are never capped.",
+            "available:true with {branch, head, subject, dirty, untracked, files}, or available:false alone. files names the files behind those counts as {path, status, added, deleted} records, capped at 20; the counts themselves are never capped. status is the two-character `git status --porcelain` code and path is the new path for a rename; added/deleted come from one `git diff --numstat HEAD` and are null where git has no delta to report (untracked, binary, renamed, or no commit to diff against).",
         },
         404: { description: "Lane not found." },
       },