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/i18n/locales/en/lanes.json

@@ -54,7 +54,7 @@
   "worktrees.heading_other": "{{count}} worktrees",
   "addLaneTitlePlaceholder": "Optional",
   "autoStage": "auto: {{stage}}",
-  "cardId": "Lane {{id}}",
+  "reorderHint": "Drag to reorder · Alt+←/→",
   "confirmRemoveCancel": "Cancel",
   "confirmRemoveConfirm": "Remove",
   "confirmRemoveMessage": "This action cannot be undone.",
@@ -93,12 +93,17 @@
   "destructive.reset.title": "Reset managed worktree?",
   "destructive.warning.no-remote": "No Git remote is configured, so nothing here is backed up remotely. You can still proceed.",
   "emptyState": "No lanes yet. Create one from a working directory:",
+  "git.filesHeading_one": "{{count}} file changed",
+  "git.filesHeading_other": "{{count}} files changed",
+  "git.filesMore_one": "… and {{count}} more file",
+  "git.filesMore_other": "… and {{count}} more files",
+  "git.noDelta": "new",
   "git.uncommitted": "{{dirty}} modified · {{untracked}} untracked",
   "kind.adopted": "adopted",
   "kind.managed": "managed",
   "laneDetail.hide": "Hide details",
   "laneDetail.show": "Lane details",
-  "laneHeader": "Lane {{id}} · {{title}}",
+  "renameLabel": "Rename this lane",
   "locks.held_one": "{{count}} lock held",
   "locks.held_other": "{{count}} locks held",
   "moreActions": "More actions",

client/src/i18n/locales/vi/lanes.json

@@ -54,7 +54,7 @@
   "worktrees.heading_other": "{{count}} worktree",
   "addLaneTitlePlaceholder": "Không bắt buộc",
   "autoStage": "tự động: {{stage}}",
-  "cardId": "Làn đường {{id}}",
+  "reorderHint": "Kéo để sắp xếp · Alt+←/→",
   "confirmRemoveCancel": "Hủy",
   "confirmRemoveConfirm": "Xóa",
   "confirmRemoveMessage": "Hành động này không thể hoàn tác.",
@@ -93,12 +93,17 @@
   "destructive.reset.title": "Đặt lại worktree được quản lý?",
   "destructive.warning.no-remote": "Chưa cấu hình Git remote, nên không có bản sao lưu ở xa. Bạn vẫn có thể tiếp tục.",
   "emptyState": "Chưa có làn đường nào. Tạo một từ thư mục làm việc:",
+  "git.filesHeading_one": "{{count}} tệp thay đổi",
+  "git.filesHeading_other": "{{count}} tệp thay đổi",
+  "git.filesMore_one": "… và {{count}} tệp nữa",
+  "git.filesMore_other": "… và {{count}} tệp nữa",
+  "git.noDelta": "mới",
   "git.uncommitted": "{{dirty}} đã sửa · {{untracked}} chưa theo dõi",
   "kind.adopted": "đã nhận",
   "kind.managed": "được quản lý",
   "laneDetail.hide": "Ẩn chi tiết",
   "laneDetail.show": "Chi tiết lane",
-  "laneHeader": "Làn đường {{id}} · {{title}}",
+  "renameLabel": "Đổi tên làn đường này",
   "locks.held_one": "Đang giữ {{count}} khóa",
   "locks.held_other": "Đang giữ {{count}} khóa",
   "moreActions": "Thêm hành động",