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).

openapi.yaml

@@ -3428,12 +3428,13 @@ components:
         permissionMode:
           type: string
           enum:
+            - auto
             - acceptEdits
             - default
             - plan
             - bypassPermissions
-          description: Permission mode passed via `--permission-mode`. Defaults to `acceptEdits` when omitted or invalid.
-          example: acceptEdits
+          description: Permission mode passed via `--permission-mode`. Defaults to `auto` when omitted or invalid.
+          example: auto
         effort:
           type: string
           enum:
@@ -3611,12 +3612,13 @@ components:
           type: string
           nullable: true
           enum:
+            - auto
             - acceptEdits
             - default
             - plan
             - bypassPermissions
           description: Permission mode recorded at spawn time.
-          example: acceptEdits
+          example: auto
         effort:
           type: string
           nullable: true
@@ -3792,13 +3794,14 @@ components:
         permissionMode:
           type: string
           enum:
+            - auto
             - acceptEdits
             - default
             - plan
             - bypassPermissions
-          default: acceptEdits
-          description: Permission mode passed via `--permission-mode`. Unknown values silently fall back to `acceptEdits`.
-          example: acceptEdits
+          default: auto
+          description: Permission mode passed via `--permission-mode`. Unknown values silently fall back to `auto`.
+          example: auto
     RunSpawnConcurrencyResponse:
       type: object
       description: HTTP 429 body when the concurrency cap is reached (ECONCURRENCY). In addition to the standard `error` envelope, this response carries a top-level `running` array listing the runs currently occupying the cap.