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/components/lanes/__tests__/LaneStripCard.test.tsx

@@ -1,13 +1,13 @@
 /**
- * @file Rendering tests for the Workspace lane tile, focused on the amber
- * "detected" badge: it may only appear when the inferred stage is genuinely
- * AHEAD of the declared one, including when the declaration used a node alias
- * (which is most of what the ship-feature skill declares).
+ * @file Rendering tests for the Workspace lane tile: the amber "detected"
+ * badge (it may only appear when the inferred stage is genuinely AHEAD of the
+ * declared one, including when the declaration used a node alias — which is
+ * most of what the ship-feature skill declares), and the reorder handles.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
-import { describe, it, expect } from "vitest";
-import { render, screen } from "@testing-library/react";
+import { describe, it, expect, vi } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
 import LaneStripCard from "../LaneStripCard";
 import type { Lane, LaneNode } from "../../../lib/types";
 
@@ -63,8 +63,10 @@ describe("LaneStripCard detected badge", () => {
     render(
       <LaneStripCard
         lane={lane({ detected_stage: "review" })}
+        index={0}
         selected={false}
         onSelect={() => {}}
+        onReorder={() => {}}
       />
     );
     expect(screen.getByTestId("lane-tile-auto-1")).toHaveTextContent("review");
@@ -77,8 +79,10 @@ describe("LaneStripCard detected badge", () => {
     render(
       <LaneStripCard
         lane={lane({ stage: "tests", detected_stage: "implementing" })}
+        index={0}
         selected={false}
         onSelect={() => {}}
+        onReorder={() => {}}
       />
     );
     expect(screen.queryByTestId("lane-tile-auto-1")).toBeNull();
@@ -88,10 +92,104 @@ describe("LaneStripCard detected badge", () => {
     render(
       <LaneStripCard
         lane={lane({ stage: "tests", detected_stage: "review" })}
+        index={0}
         selected={false}
         onSelect={() => {}}
+        onReorder={() => {}}
       />
     );
     expect(screen.getByTestId("lane-tile-auto-1")).toHaveTextContent("review");
   });
 });
+
+describe("LaneStripCard reorder", () => {
+  /** jsdom ships no DataTransfer, so the drag events carry a stub store. */
+  function dataTransfer(initial = "") {
+    let payload = initial;
+    return {
+      setData: (_type: string, v: string) => {
+        payload = v;
+      },
+      getData: () => payload,
+      effectAllowed: "",
+      dropEffect: "",
+    };
+  }
+
+  it("reports the dragged tile's index and the drop target's", () => {
+    const onReorder = vi.fn();
+    const dt = dataTransfer();
+    render(
+      <>
+        <LaneStripCard
+          lane={lane({ id: 1 })}
+          index={0}
+          selected={false}
+          onSelect={() => {}}
+          onReorder={onReorder}
+        />
+        <LaneStripCard
+          lane={lane({ id: 2 })}
+          index={2}
+          selected={false}
+          onSelect={() => {}}
+          onReorder={onReorder}
+        />
+      </>
+    );
+    fireEvent.dragStart(screen.getByTestId("lane-tile-1"), { dataTransfer: dt });
+    fireEvent.drop(screen.getByTestId("lane-tile-2"), { dataTransfer: dt });
+    expect(onReorder).toHaveBeenCalledWith(0, 2);
+  });
+
+  it("ignores a drop carrying no tile index", () => {
+    const onReorder = vi.fn();
+    render(
+      <LaneStripCard
+        lane={lane({})}
+        index={0}
+        selected={false}
+        onSelect={() => {}}
+        onReorder={onReorder}
+      />
+    );
+    fireEvent.drop(screen.getByTestId("lane-tile-1"), { dataTransfer: dataTransfer("nonsense") });
+    expect(onReorder).not.toHaveBeenCalled();
+  });
+
+  it("moves the focused tile with Alt+Arrow, the keyboard path for reordering", () => {
+    const onReorder = vi.fn();
+    render(
+      <LaneStripCard
+        lane={lane({})}
+        index={2}
+        selected={false}
+        onSelect={() => {}}
+        onReorder={onReorder}
+      />
+    );
+    const tile = screen.getByTestId("lane-tile-1");
+    fireEvent.keyDown(tile, { key: "ArrowLeft", altKey: true });
+    expect(onReorder).toHaveBeenCalledWith(2, 1);
+    fireEvent.keyDown(tile, { key: "ArrowRight", altKey: true });
+    expect(onReorder).toHaveBeenCalledWith(2, 3);
+    // A bare arrow is the strip's own scroll/focus movement, not a reorder.
+    fireEvent.keyDown(tile, { key: "ArrowLeft" });
+    expect(onReorder).toHaveBeenCalledTimes(2);
+  });
+
+  it("shows the id without the 'Lane' prefix", () => {
+    render(
+      <LaneStripCard
+        lane={lane({ id: 7, title: "checkout flow" })}
+        index={0}
+        selected={false}
+        onSelect={() => {}}
+        onReorder={() => {}}
+      />
+    );
+    const tile = screen.getByTestId("lane-tile-7");
+    expect(tile).toHaveTextContent("#7");
+    expect(tile.textContent).not.toMatch(/Lane/i);
+  });
+});