Merge branch 'main' into dev

Surgical merge of 74 commits from main into dev. Key features ported:

- Provider visibility gating (appVersion filtering for Pi/Copilot)
- Pi agent provider + Copilot re-enabled
- Provider-declared features system (Codex fast mode)
- Workspace dedup by worktree root (adapted to integer IDs)
- Bulk close archiving fix for stored agents
- Agent creation timeout increase to 60s
- Audio/voice crash fixes (external buffer copies)
- Multi-host setup fix
- Reload agent tab action

Dev architecture preserved: SQLite storage, service proxy,
workspace setup dialog, hover cards, removed launcher tabs.

CLAUDE.md

@@ -47,6 +47,12 @@ See [docs/DEVELOPMENT.md](docs/DEVELOPMENT.md) for full setup, build sync requir
 - **NEVER assume a timeout means the service needs restarting** — timeouts can be transient.
 - **NEVER add auth checks to tests** — agent providers handle their own auth.
 - **Always run typecheck after every change.**
+- **NEVER make breaking changes to WebSocket or message schemas.** The mobile app in the App Store always lags behind the daemon, and daemons in the wild lag behind new app releases. Both directions must work. Every schema change MUST be backward-compatible:
+  - New fields: always `.optional()` with a sensible default or `.transform()` fallback.
+  - Never change a field from optional to required.
+  - Never remove a field — deprecate it (keep accepting it, stop sending it).
+  - Never narrow a field's type (e.g. `string` → `enum`, `nullable` → non-null).
+  - Test with: "does a 6-month-old client still parse this?" and "does a 6-month-old daemon still send something this client accepts?"
 
 ## Debugging