feat(run,ui): make the lane console usable — terminal focus, live-exit recovery, auto permission mode, model aliases

Terminal (issue #33):
- `convertEol` is gone from xterm. It rewrote every bare LF as CR+LF, so a
  tmux pane that scrolled (tmux emits a bare LF and keeps drawing at the
  column it was on) had the rest of that draw land at column 0, stamping a
  line's first characters into the left margin of the rows below — the torn
  left edge that only showed up once content scrolled.
- The attach carries the client's real size (`?cols=&rows=`, `sizeFromQuery`
  in `server/websocket.js`, bounded because it reaches a TIOCSWINSZ ioctl).
  `attach()` spawned `tmux attach-session` at a hardcoded 80x24 on every
  attach, and tmux sizes the window to the newest client, so `claude` redrew
  its whole UI at 80 columns until the first `resize` message landed.
- The terminal takes the keyboard on mount, so typing reaches tmux without
  clicking the pane first.
- A pane that ends (double Ctrl+C, `exit`, a crash) reports itself through a
  new `onExit` prop and `LaneConsolePane` runs `newRun()`, so the console
  returns to the setup form instead of leaving a dead pane behind a
  "New run" button.

Pane environment:
- `server/lib/desktop-env.js` forwards the graphical session's DISPLAY /
  WAYLAND_DISPLAY / XAUTHORITY / XDG_RUNTIME_DIR (from
  `systemctl --user show-environment`, this process's own values winning)
  into the pane. The server normally runs as a systemd user service with none
  of them, so `claude` there could not read the clipboard and answered "no
  image found in clipboard" on every image paste.

Run setup:
- `auto` is a permission mode and is now the default everywhere — allowlists,
  the `--permission-mode` fallback, the select, and the pane's initial state.
- The model picker sends the CLI's aliases (`fable`/`opus`/`sonnet`/`haiku`)
  instead of pinned ids. `claude --model` resolves an alias to the latest
  model itself, so a release like Fable 5.1 needs no edit here; pricing is
  unaffected because it keys off the resolved id the transcript reports.
- **Create/update readme file** moved from the Add-lane modal into the lane's
  Tools menu: creating a lane and writing its docs are separate decisions,
  and the second is worth re-running long after the first.
- The Workspace's no-lane state is a real banner; the lane strip (add tile
  included) renders only once a lane exists.

Refs #32, #33.

Tests: npm run test:server (1828 pass), client vitest (558 pass).

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

@@ -16,6 +16,9 @@
   "actions.syncCheckClean": "DEV_DELTA: {{count}} file(s), overlap: {{overlap}}",
   "actions.syncCheckCollision": "Migration collision: {{file}} → rename to {{suggestion}}",
   "actions.tools": "Tools",
+  "actions.writeDocs": "Create/update readme file",
+  "actions.writeDocsHint": "Opens this lane's terminal and runs /sg-all:sg-md-writing there: creates CLAUDE.md/AGENTS.md if missing, or updates them concisely if they already exist.",
+  "actions.writeDocsResult": "Started — see this lane's terminal.",
   "add": "Add lane",
   "addLane": "Create a lane from a working directory",
   "addLaneBaseLabel": "Branch to fork from",
@@ -49,8 +52,6 @@
   "addLaneToolClaude": "Claude Code",
   "addLaneToolCodex": "Codex",
   "addLaneToolHint": "Which CLI drives this lane. Cannot be changed later.",
-  "addLaneWriteDocsHint": "On creation, opens the lane's terminal and runs /sg-all:sg-md-writing there: creates CLAUDE.md/AGENTS.md if missing, or updates them concisely if they already exist.",
-  "addLaneWriteDocsLabel": "Create/update readme file",
   "autoStage": "auto: {{stage}}",
   "browse.button": "Browse",
   "browse.empty": "This folder is empty.",
@@ -93,7 +94,8 @@
   "destructive.reset.survives": "Gitignored files such as node_modules and .env are kept; untracked files are deleted.",
   "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:",
+  "empty.body": "A lane is one working directory the dashboard follows — its pipeline, sessions and terminal. Add one here, or from a terminal:",
+  "empty.title": "No lanes yet",
   "features.archived": "archived",
   "features.live": "Live",
   "features.viewingArchived": "Viewing archived feature \"{{slug}}\" — the lane keeps running; this is a read-only snapshot.",

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

@@ -71,7 +71,8 @@
     "modelCustom": "Custom…",
     "modelCustomPlaceholder": "model id (e.g. claude-opus-5)",
     "modelInheritLabel": "Inherit from settings",
-    "permissionAcceptEdits": "acceptEdits (recommended)",
+    "permissionAcceptEdits": "acceptEdits (file edits without asking)",
+    "permissionAuto": "auto (recommended - asks only for risky actions)",
     "permissionBypass": "bypassPermissions (DANGER - allows everything without asking)",
     "permissionDefault": "default (interactive prompts - sessions may hang headlessly)",
     "permissionMode": "Permission mode",