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.

client/src/lib/laneOrderStorage.ts

@@ -0,0 +1,69 @@
+/**
+ * @file laneOrderStorage.ts
+ * @description Persists the Workspace lane strip's user-chosen card order to
+ * localStorage, the same read/validate/fallback convention as
+ * splitViewStorage.ts.
+ *
+ * The order lives in the browser rather than the lanes table on purpose: it is
+ * a per-viewer preference, like the split-pane layout beside it, and nothing
+ * server-side (the CLI's `agenthub lanes`, the pipeline-stats picker) has an
+ * opinion about it. Ceiling: the order does not follow the user to another
+ * browser or to the CLI — move it to a `lanes.sort_order` column if it ever
+ * must.
+ *
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+const STORAGE_KEY = "agenthub.workspace.laneOrder";
+
+export function readLaneOrder(): number[] {
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY);
+    if (!raw) return [];
+    const parsed: unknown = JSON.parse(raw);
+    if (!Array.isArray(parsed)) return [];
+    return parsed.filter((id): id is number => typeof id === "number");
+  } catch {
+    return [];
+  }
+}
+
+export function writeLaneOrder(ids: number[]): void {
+  try {
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(ids));
+  } catch {
+    /* ignore quota / disabled storage */
+  }
+}
+
+/**
+ * Applies a stored id order to a freshly fetched lane list.
+ *
+ * Ids the stored order never saw — a lane created since, or created in another
+ * tab — keep their server order (id ascending) and land at the END, so a new
+ * lane appears predictably rather than wherever a stale index puts it. Stored
+ * ids naming a lane that no longer exists are simply skipped.
+ *
+ * @param lanes Lanes in server order.
+ * @param order Stored id order.
+ * @returns A new array; the input is never mutated.
+ */
+export function sortByStoredOrder<T extends { id: number }>(lanes: T[], order: number[]): T[] {
+  const rank = new Map(order.map((id, i) => [id, i]));
+  const known = lanes
+    .filter((l) => rank.has(l.id))
+    .sort((a, b) => rank.get(a.id)! - rank.get(b.id)!);
+  const fresh = lanes.filter((l) => !rank.has(l.id));
+  return [...known, ...fresh];
+}
+
+/**
+ * Moves the lane at `from` to index `to`, returning the resulting id order.
+ * Out-of-range indices yield the unchanged order rather than a hole.
+ */
+export function moveLane(ids: number[], from: number, to: number): number[] {
+  if (from === to || from < 0 || to < 0 || from >= ids.length || to >= ids.length) return ids;
+  const next = [...ids];
+  next.splice(to, 0, ...next.splice(from, 1));
+  return next;
+}