Phase 1 — sub-agent todo isolation (backend):
- Add current_todo_session_id ContextVar; subagent_runner scopes it to the
  sub-agent's ephemeral run id so its auto-populated plan and todo updates
  land in an isolated KV row instead of clobbering the parent session's todo
  (which the parent's goal-anchoring reads every iteration).
- todo._sid() and planning.set_tasks prefer current_todo_session_id; the
  parent run leaves it unset, so all existing todo consumers (anti-stall,
  goal anchor, get_progress_message) behave exactly as before.

Phase 2 — live todo in the TUI right column:
- TodoUpdated event + emit it from the agent loop after planning auto-populate
  and after each tool-execution turn.
- GET /sessions/{id}/todos reads the parent session's todo KV row (explicit
  user_id/session_id, optional injected kv).
- api.get_todos + TodoList/TodoPanel widgets: status-coloured markers
  (pending dim, in_progress accent+bold, done success, failed error, skipped
  dim), progress header, scrollable panel below the auto-height info block.
- Hybrid delivery: REST seeds the panel on attach/switch, todo_updated WS
  events update it live.

Sub-agent todos as nested sub-lists is deferred to a later phase.

Co-Authored-By: Claude <noreply@anthropic.com>

Show a non-interactive list of matching commands above the input box while
the user types a '/'-command (no whitespace yet). Tab completes the prefix to
the canonical name of the top match. Enter already routed '/...' through
_run_command, so submitting a typed command executes it instead of sending
it to the agent — unchanged.

- CommandRegistry.match(prefix): case-insensitive prefix match on name and
  aliases, exact match sorted first; empty prefix returns all.
- CommandHints(Static): purely visual, never takes focus, hidden by default.
- InputBox composes hints above the prompt and refreshes them on
  TextArea.Changed.

Co-Authored-By: Claude <noreply@anthropic.com>

Drop the SessionsPanel widget and all dead code wired to it (handlers,
broadcast helper, session-list events, _refresh_sessions worker). The
/new, /sessions, /switch commands are preserved — they already operate
via app.attach_session / chat output rather than the panel.

Co-Authored-By: Claude <noreply@anthropic.com>

Add an animated "agent is working" indicator so a silent gap (long-running
tool, the pause before the first token, sub-agent reasoning) reads as
"alive" rather than "hung": a braille spinner + phase label that runs on
its own timer, independent of the WebSocket event flow.

- New ActivityIndicator widget (rotating spinner + phase label, colored
  status_online), started/stopped from tui_app WS phase transitions
  (thinking / responding / planning / running <tool>) and stopped on
  stream_end/stopped/error and on connection drop.
- New StatusBar bottom line replaces Textual's Footer: indicator on the
  left, dim key-combo summary on the right. One line instead of the menu;
  the key bindings themselves stay on the App so the keys still work.
- Input box: TextArea min-height 3 -> 1, so the prompt is one line by
  default (auto-resize + max-height 12 unchanged).

Co-Authored-By: Claude <noreply@anthropic.com>

- Add right-side SessionsPanel widget (DataTable) listing server sessions.
- Wire SessionsPanel into TUI layout and session selection flow.
- Add SessionSelected / SessionListUpdated events and refresh logic.
- Implement /export slash command: markdown rendering + $EDITOR.
- Update /new, /sessions, /switch, /profile to use session_id/name/preview.
- Add integration tests for SessionsPanel and /export; update layout test.
- Update docs/navi_code_cli.md with new panel and command.

Co-Authored-By: Claude <noreply@anthropic.com>

- Add clients/terminal/tui package with micro-architecture:
  - events, context, chat_model, ws_bridge, permissions engine.
  - widgets: ChatPanel, StatusPanel, InputBox.
  - renderers: user/assistant messages, thinking, tool calls, errors,
    markdown, plain — registry-based and extensible.
  - slash commands: /help, /new, /sessions, /switch, /profile, /thinking,
    /compact, /quit — registry-based and extensible.
- Wire navi-code to launch TUI by default; keep click-CLI via --raw.
- Add textual>=0.70 dependency.
- Add TUI smoke tests via Textual Pilot.
- Add docs/plan_navi_code_tui.md with full Phase 4/5 roadmap.

Tests: 463 passed, 1 skipped (excluded unrelated websocket test).

Co-Authored-By: Claude <noreply@anthropic.com>