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/components/run/LaneConsolePane.tsx

@@ -75,7 +75,7 @@ export function LaneConsolePane({
 
   const [prompt, setPrompt] = useState("");
   const [model, setModel] = useState("");
-  const [permissionMode, setPermissionMode] = useState<PermissionMode>("acceptEdits");
+  const [permissionMode, setPermissionMode] = useState<PermissionMode>("auto");
   const [effort, setEffort] = useState<EffortLevel>("");
   const [cwd, setCwd] = useState(() => lanes.find((l) => l.id === laneId)?.cwd ?? defaultCwd ?? "");
   const [resumeSession, setResumeSession] = useState<Session | null>(null);
@@ -491,6 +491,13 @@ export function LaneConsolePane({
           <TerminalView
             runId={handle!.id}
             wsBaseUrl={window.location.origin.replace(/^http/, "ws")}
+            // The pane died (double Ctrl+C out of `claude`, `exit`, a crash) —
+            // go straight back to the setup form rather than leaving a dead
+            // terminal the user has to click "New run" out of.
+            onExit={() => {
+              newRun();
+              refreshList();
+            }}
           />
           <button
             onClick={newRun}