feat: AI commit messages, change tree, router behavesAs, sidebar times (v2.2.0)

- Changes panel: Files and Changes merged into one panel; the overview's
  groups drawn as a folder tree (compacted chains, file counts, fold,
  stage/unstage a whole folder)
- AI-suggested commit message for what is staged
  (POST /api/lanes/:id/git/commit-message, claude -p --safe-mode, haiku)
- AI Router: optional "Behaves as" Claude model id, written as
  modelPicker options into the router's --settings file (issue #56)
- Sidebar: session rows show last activity, live rows their start time;
  a closed Terminal row can be removed (DELETE /api/run/history/:id)
- Every pane's CLI starts only once a client is attached; claude panes
  no longer forced inline; tmux scrollbar one column wide
- Update notifier: "Check for updates" reopens a closed notice

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

@@ -59,6 +59,7 @@
   "changes.collapseFile": "Collapse {{path}}",
   "changes.commitPlaceholder": "Commit message",
   "changes.commitStaged": "Commit {{count}} staged",
+  "changes.suggestMessage": "Suggest a commit message with AI (Claude, staged changes)",
   "changes.conflicted": "conflict",
   "changes.discard": "Discard this file's changes",
   "changes.discardConfirm": "Click again to discard — this cannot be undone",
@@ -82,7 +83,7 @@
   "changes.loading": "Reading the working copy…",
   "changes.mode.browse": "Files",
   "changes.mode.history": "History",
-  "changes.mode.overview": "Overview",
+  "changes.mode.overview": "Changes",
   "changes.mode.review": "Review",
   "changes.noCommits": "No commits yet.",
   "changes.noHunks": "No textual change.",
@@ -98,6 +99,10 @@
   "changes.size.compact": "Narrow",
   "changes.size.half": "Medium",
   "changes.size.full": "Full screen",
+  "changes.fileCount_one": "{{count}} file",
+  "changes.fileCount_other": "{{count}} files",
+  "changes.stageFolder": "Stage every file in this folder",
+  "changes.unstageFolder": "Unstage every file in this folder",
   "changes.stageAll": "Stage all ({{count}})",
   "changes.unstageAll": "Unstage all ({{count}})",
   "changes.dropEdits": "Discard your unsaved edits to this file?",
@@ -299,7 +304,6 @@
   "menu.copyPath": "Copy path",
   "menu.reset": "Reset worktree…",
   "menu.remove": "Delete workspace…",
-  "panel.files": "Files",
   "panel.changes": "Changes",
   "panel.analyst": "Analyst",
   "replay.placeholder": "Message to continue this session…",
@@ -323,6 +327,8 @@
   "tree.newSession": "New session",
   "tree.noSessions": "No sessions yet",
   "tree.closedTerminal": "Closed terminal — click opens a new one in this workspace's folder (Ctrl/Cmd+click: in a split)",
+  "tree.reopenTerminal": "Open a new terminal",
+  "tree.forgetTerminal": "Remove from list",
   "tree.transcriptHint": "No live pane — opens its conversation; a message you send resumes it",
   "tree.splitHint": "Live pane — Ctrl/Cmd+click opens it in a split beside the focused pane",
   "tree.renameSession": "Rename session",

client/src/i18n/locales/en/settings.json

@@ -587,6 +587,8 @@
     "fieldApiKeyKeep": "Leave blank to keep the saved key.",
     "fieldModel": "Model",
     "fieldModelHint": "Used for every tier unless you override one below. Many routers accept one symbolic name.",
+    "fieldBehavesAs": "Behaves as (Claude Code)",
+    "fieldBehavesAsHint": "Optional. The Claude model id Claude Code should treat this router's model names as (effort defaults, context window), e.g. claude-opus-5-5. Fill it in when Claude Code says a model isn't described by its model catalog, and name the model the router really sends to. While set, it replaces your own modelPicker setting in these sessions.",
     "perTier": "Per-tier overrides",
     "perTierHint": "Leave a field blank to use the model above.",
     "tier": {