feat(native): complete TV-SIDECHAT and TV-LINEAGE parity - #365

Native client side chat and thread lineage were missing capability checks, post-fork removal recovery, unlisted parent/child title fetching, workflow phase/elapsed parity, linked-environment lineage rows, live session detach, and legacy ultracode/selectable-model/Claude-version badge handling present on web. This brings TV-SIDECHAT and TV-LINEAGE to parity with web and marks both rows done in apps/native/parity/LEDGER.md.

Ref #243 · Closes #287 · Closes #283 · Ref #296

Changes

• TV-SIDECHAT (Closes #287, upstream pingdotgg/t3code#31114):
  • Omit forced runtimeMode override on first_message_command.
  • Gate side-chat offering, open (fork_command), failed-start discard, closed cleanup (delete_command), bring-back, delete, and post mutations on orchestration:operate scope (AppState::can_operate_threads, side_chat::Parent::can_operate, side_chat::offered, bring_back_blocked_reason).
  • Guard continue_side_chat_start against side-chat threads removed after fork creation ("The side chat is no longer available." + discard cleanup).
• TV-LINEAGE (Closes #283, upstream pingdotgg/t3code#29000):
  • Exclude omitted family mounts and snapshot.archived_threads from listed_set before computing unlisted_title_ids, filter hidden threads and hidden unloaded relations, and prefer getThreadTitles resolved titles over shell node titles for rows and merge targets.
  • Fetch unlisted parent/child titles via orchestration.getThreadTitles in ThreadTitlesFeed keyed by (connection, unlisted_ids, removed_at), clearing active_key alongside in_flight on failure with bounded backoff retry (allow_retry() on AppEvent), and forwarding this.card_open from DetailsView so closed details cards do not fire RPCs.
  • Preserve groups.related, groups.active, and groups.previous ("Previous agents", collapsed by default), update workflow edge status before group_relationships, render Lineage · N running / Side chats · N running headings, and keep Lineage visible (has_lineage() / lineage_len()) when only unlinked running subagents, delegated_from, remote_subagents, or can_detach && !side_chats.is_empty() exist.
  • Add AgentTiming and LiveAgentElapsed (AgentElapsed.tsx full 1m 05s and compact 1m/1.5h/12h formats) on subagent rows (deriving non-workflow timing from agent.current(node)), workflow member rows, and workflow phase headers; wrap Entity<LiveAgentElapsed> inside window.use_keyed_state with deferred refresh so 1s ticks redraw only the timer view without notifying DetailsView mid-render; auto-open workflow phases on Pending -> Running via Option<bool> state; show Failed destructive labels, {settled}/{total} agent(s) counts, phase elapsed, and "No agents yet" empty workflow placeholders.
  • Add DelegatedFromRow, RemoteSubagentRow, linked-environment target navigation (open_linked_thread), and "More thread actions" -> "Disconnect agent session" (can_detach_provider_session / detach_session_commands, gated on orchestration:operate).
  • Gate merge/stop/child-approval/detach actions behind orchestration:operate.
• Subagent & Child Traits (Ref #296, upstream pingdotgg/t3code#27034 — keeping #296 open for CO-TRAITS):
  • Handle legacy ultracode -> xhigh effort fallback and resolved-slug matching, resolve_selectable_model fallback, and collapse_claude_minor_version badge collapsing in ComposerLineage::read_bar.

Verification (6411dd79bd)

• cargo test -p t3-core -p t3-client: t3-core 1343 unit + 8 conformance passed; t3-client 108 unit passed.
• cargo test -p t3-native --features snapshot -- side_chat:: lineage:: thread_details:: --test-threads=1: 12 passed, 0 failed (172 filtered out).
• cargo clippy --workspace --all-targets -- -D warnings: passed (0 errors/warnings).
• cargo build -p t3-native --bin t3-native --features snapshot: passed.
• node --test apps/native/parity/sync.test.ts: 42/42 passed.
• Note: vp fmt --check and pnpm-backed conformance --check / gen-theme --check were not run directly inside this worktree (vp i skipped); theme inputs and conformance fixtures were untouched (t3-core conformance suite passed 8/8).

Snapshots (1440x900)

Surface	Dark	Light
Thread Details + Lineage (Previous agents expanded, AgentElapsed)
Open SideChatPane right-panel tab
ComposerLineage (ProviderSubagentBar)

Model: Gemini 3.1 Pro (Antigravity)