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/__tests__/TerminalView.test.tsx

@@ -16,6 +16,7 @@ const openMock = vi.fn();
 const disposeMock = vi.fn();
 const wheelHandlerMock = vi.fn();
 const keyHandlerMock = vi.fn();
+const focusMock = vi.fn();
 const loadAddonMock = vi.fn();
 // Mutable stand-ins for the two live terminal facts the wheel handler reads.
 const termState = {
@@ -54,6 +55,7 @@ vi.mock("@xterm/xterm", () => ({
     loadAddon: loadAddonMock,
     attachCustomWheelEventHandler: wheelHandlerMock,
     attachCustomKeyEventHandler: keyHandlerMock,
+    focus: focusMock,
   })),
 }));
 vi.mock("@xterm/addon-fit", () => ({
@@ -100,13 +102,27 @@ describe("TerminalView", () => {
     keyHandlerMock.mockClear();
     loadAddonMock.mockClear();
     openMock.mockClear();
+    focusMock.mockClear();
   });
 
   afterEach(cleanup);
 
-  it("opens a WS connection to the run's ws-pty path", () => {
+  it("opens a WS connection to the run's ws-pty path, carrying its own size", () => {
+    // The size rides on the attach URL, not on a `resize` message sent after
+    // it: tmux resizes the window to the newest client, so attaching at the
+    // server's default 80x24 makes claude redraw its UI at 80 columns and
+    // leaves that width in the scrollback (issue #33).
     render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
     expect(MockWebSocket.instances).toHaveLength(1);
+    expect(MockWebSocket.instances[0]!.url).toBe(
+      "ws://localhost:4820/ws-pty/agenthub-lane-1?cols=131&rows=28"
+    );
+  });
+
+  it("omits the size when the terminal has none yet (a collapsed console is 0x0)", () => {
+    termState.cols = 0;
+    termState.rows = 0;
+    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
     expect(MockWebSocket.instances[0]!.url).toBe("ws://localhost:4820/ws-pty/agenthub-lane-1");
   });
 
@@ -184,6 +200,24 @@ describe("TerminalView", () => {
     expect(preventPlainTab).not.toHaveBeenCalled();
   });
 
+  it("takes the keyboard as soon as it mounts", () => {
+    // The terminal IS the page here — without this the first thing typed after
+    // opening a lane went nowhere until the user clicked the pane.
+    render(<TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" />);
+    expect(focusMock).toHaveBeenCalled();
+  });
+
+  it("tells its owner when the pane exited, so the setup form can come back", () => {
+    // A double Ctrl+C out of `claude` ends the tmux session; the dead pane used
+    // to sit there until the user found the "New run" button.
+    const onExit = vi.fn();
+    render(
+      <TerminalView runId="agenthub-lane-1" wsBaseUrl="ws://localhost:4820" onExit={onExit} />
+    );
+    MockWebSocket.instances[0]!.onmessage?.({ data: '{"type":"exit","code":0}' });
+    expect(onExit).toHaveBeenCalledTimes(1);
+  });
+
   it("renders through the canvas addon, not xterm's DOM renderer", () => {
     // The DOM renderer aligns a row with one `letter-spacing`, which holds only
     // while every glyph shares a font. Vietnamese diacritics and CJK fall to a