v2 Ctrl+S freeze: defer reset() + cleanup via call_after_refresh so the
keystroke handler returns immediately even when streaming has the
reactive queue saturated. Added _skip_change_next flag to short-circuit
on_input_area_changed during the deferred clear.

v3 terminal title: route _set_term_title via os.write(1,...) — sys.stdout
gets redirected to sb_agent.log during PTK app run, so OSC 0 escapes
were silently ending up in the log file. Default _session_name = 'session'
for v2 parity, and repaint title on running→idle transition.

v3 input row bg fill: _tile() now pads explicit bg-active spaces to
width — PTK's cell renderer doesn't honour \x1b[K (erase-to-EOL), so
the user bubble's charcoal band used to stop at text length.

v3 /emoji picker: arrow-key menu (mirrors /llm). Pet styles cleaned to
bear (default) + cat + dot + unicode. Bear calm tier restored to ʕ•ᴥ•ʔ.
• used for the calm tier, o for focused — matches user-requested mood
progression. Pet frame rate decoupled from spinner via self._spin // 5.

v3 ask_user "coderun freeze" fix: _tool_status no longer marks an
in-flight ask_user chip as ✓ ok when the stream contains the
"Waiting for your answer ..." marker. Bumped DoneEvent grace from 2 s
to 10 s when the marker is in the stream so a slow ask_user_queue.put
doesn't cause the picker to fall through to _finalize.

v3 /scheduler picker: added pre_checked kwarg to _show_menu so the
running set lands atomically. slash_cmds._match_service relaxed to
path-only matching so directly-launched (`python reflect/foo.py`)
reflect tasks are detected. Running rows highlighted in functional
green. Confirm card accepts ← as cancel (parity with Esc) — same on
v2 ChoiceList.

v3 keybindings: Esc Esc (within 800 ms) → /rewind (handled in
_handle_key so PTK's Esc interception path actually fires).

v3 pending input queue: agent.task_dir wired so ga.turn_end_callback
can consume `<task_dir>/_intervene`. New AgentBridge.inject_intervene
appends to the file (atomic vs read-modify-write), and _drain_pending
routes the combined message either through that hook (mid-turn) or via
put_task (idle). Cooldown 5 s, resets per new pending. ↑ recalls the
last queued message, Esc clears the queue. v2 has equivalent shape:
AgentSession.pending + per-session agent.task_dir + _inject_intervene
+ _poll_pending timer.

! shell magic: prefix `!` enters shell mode — pink border, prompt mark
swaps `❯` → `!`, body strips the leading `!` so the glyph appears
once. Enter runs the rest as `subprocess.run(shell=True, timeout=30)`,
echoes `! cmd` + `└ output` into scrollback, and appends to LLM
history (via _intervene when agent is running, direct backend.history
append when idle — sidesteps the iterator race).

/resume: forwarded as a literal to the agent so GA's _handle_slash_cmd
(agentmain.py:124) can expand it. Added to v3 _cmds() + v2 COMMANDS +
slash_cmds.COMMANDS + i18n + /help + Tips.

Turn marker regex fix: agent_loop.py:52 switches `**LLM Running
(Turn N) ...**` to the short `**Turn N ...**` when task_dir is set.
Extended all v3/v2 turn-marker regexes to match either form.

Cherry-picked upstream fixes:
- PR #466 (8ae3645): _collapse_choice early-return when the
  on_select callback (e.g. /rewind) detaches the anchor widget.
- PR #461 (08f21e8): SelectableStatic.has_valid_selection_parent +
  app-level _is_stale_selectable_mouse_event filter that swallows
  mouse events on detached widgets.