docs: update meta files for OTEL telemetry session

.claude/CLAUDE.md

@@ -67,6 +67,7 @@
 - RemoteManager reconnection: exponential backoff (1s-30s cap) on disconnect, attempt_tcp_probe() (TCP-only, no WS upgrade), emits remote-machine-reconnecting and remote-machine-reconnect-ready events. Frontend listeners in remote-bridge.ts; machines store auto-reconnects on ready.
 - v3 workspace store (`workspace.svelte.ts`) replaces layout store for v3. Groups loaded from `~/.config/bterminal/groups.json` via `groups-bridge.ts`. State: groups, activeGroupId, activeTab, focusedProjectId. Derived: activeGroup, activeProjects.
 - v3 groups backend (`groups.rs`): load_groups(), save_groups(), default_groups(). Tauri commands: groups_load, groups_save.
+- Telemetry (`telemetry.rs`): tracing + optional OTLP export to Tempo. `BTERMINAL_OTLP_ENDPOINT` env var controls (absent = console-only). TelemetryGuard in AppState with Drop-based shutdown. Frontend events route through `frontend_log` Tauri command → Rust tracing (no browser OTEL SDK — WebKit2GTK incompatible). `telemetry-bridge.ts` provides `tel.info/warn/error()` convenience API. Docker stack at `docker/tempo/` (Grafana port 9715).
 - v3 SQLite additions: agent_messages table (per-project message persistence), project_agent_state table (sdkSessionId, cost, status per project), sessions.project_id column.
 - v3 App.svelte: VSCode-style sidebar layout. Horizontal: left icon rail (GlobalTabBar, 2.75rem, single Settings gear icon) + expandable drawer panel (Settings only, content-driven width, max 50%) + main workspace (ProjectGrid always visible) + StatusBar. Sidebar has Settings only — Sessions/Docs/Context are project-specific (in ProjectBox tabs). Keyboard: Ctrl+B (toggle sidebar), Ctrl+, (settings), Escape (close).
 - v3 component tree: App -> GlobalTabBar (settings icon) + sidebar-panel? (SettingsTab) + workspace (ProjectGrid) + StatusBar. See `docs/v3-task_plan.md` for full tree.