The last batch from the code review — real bugs and edge cases, not cosmetics:

- tui_app._resolve_session: read session_id with .get and return None when a
  malformed server response omits it, instead of KeyError slipping past the
  api-call except (5.B3).
- cli /switch: surface the original error cause (404 vs network vs server) on
  a non-unique prefix match instead of swallowing it into a generic "not found"
  (6.B2).
- input_box _complete_command: a bare "/" with no hint list available no longer
  auto-picks the first command in the registry (3.B3).
- filesystem _render_grep: when the grep ran in regex mode, highlight with the
  actual regex so marked spans match what the server found — a literal highlight
  of a regex pattern would mark nothing (2.B2).
- file_refs _collect_files: filter sensitive entries out in the generator before
  sorted() so a huge directory is not fully materialized only to be mostly
  discarded (5.P1).
- renderers/tool ToolResultRenderer: cap a generic tool result at 200 lines
  (tail + marker) so a non-filesystem tool with huge output does not flood the
  chat bubble — filesystem has its own renderer (2.P3).

Tests: malformed-response /switch error surfacing, bare-slash no-auto-pick,
grep regex highlight, sensitive-subdir skip, tool-result truncation. Full
suite: 953 passed, 1 skipped.

Sub-agent activity was either rendered as a generic tool card (spawn_agent) or
dropped to raw debug output (turn_thinking was unhandled in the TUI chat model
and the raw CLI). The webclient nests subagent events inside the spawn_agent
card; the TUI is flat, so nesting is conveyed with a distinct spawn card plus
left-indented, dimmed subagent cards.

New renderers/subagent.py:
- SpawnAgentStartedRenderer: "↘ subagent · <profile_id>" card showing the task
  (+ briefing dimmed), secondary border. Registered before ToolStartedRenderer.
- SpawnAgentResultRenderer: "↙ subagent · <profile_id> ✓/✗" card with the
  result, success/error border. Registered before ToolResultRenderer.

Nested subagent styling (left indent via Padding + dim):
- ThinkingRenderer: is_subagent → "subagent thinking" title, dim border, indented.
- PlanningStatusRenderer / PlanReadyRenderer: is_subagent → indented (label/title
  already mark it as subagent).
- ToolStartedRenderer / ToolResultRenderer: is_subagent → indented so inner
  tool calls read as nested inside the spawn card.

chat_model handles turn_thinking → thinking_block item with is_subagent meta;
chat_panel._refresh forwards is_subagent to the thinking renderer. Raw CLI
render.py prints turn_thinking as a [thinking] block (with "(subagent)" prefix).

Tests: spawn card shows profile/task and status; subagent thinking/planning/tool
cards are indented and labeled; non-subagent tool card is not indented;
turn_thinking creates a subagent thinking_block. 593 passed, 1 skipped.

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

- Register Navi themes as Textual themes so $tui-* CSS variables resolve.

- Update ChatPanel, StatusPanel, InputBox to use palette colors.

- Update all content renderers to draw from the active theme.

- Add set_active_theme/get_active_theme helpers for runtime color access.

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>