fix(butler): wire verification gaps — pain storage init, cold start, UI mode switches

- Call init_pain_storage() in Tauri .setup() so pain persistence activates on boot
- Integrate useColdStart hook into FirstConversationPrompt for auto-greeting
- Add UI mode toggle section to Settings/General (already had imports)
- Add "简洁" mode switch-back button to TopBar in professional layout
- Update SemanticSkillRouter @reserved annotation to reflect active status

crates/zclaw-skills/src/semantic_router.rs

@@ -5,9 +5,8 @@
 //! 2. Optional embedding similarity (when an Embedder is configured)
 //! 3. Optional LLM fallback for ambiguous cases
 //!
-//! **@reserved** — This module is fully implemented (719 lines, 200+ lines of tests)
-//! but NOT yet wired into the message pipeline. It will be activated in Phase 3
-//! when the "butler mode" semantic auto-routing feature is enabled. Do NOT delete.
+//! **Active** — Used by `ButlerRouterMiddleware` (zclaw-runtime) for keyword-based routing.
+//! The full TF-IDF + embedding pipeline can be integrated via `with_router()` when needed.
 
 use std::collections::HashMap;
 use std::sync::Arc;