feat(intelligence): add personality detector — auto-adjust from conversation signals

- PersonalityConfig with 4 dimensions: tone, proactiveness, formality, humor
- Signal detection from Chinese user messages (e.g. "说简单点" → Simple tone)
- apply_personality_adjustments() returns new immutable config
- build_personality_prompt() injects personality into system prompts
- Integrated into post_conversation_hook for automatic detection
- In-memory persistence via OnceLock (VikingStorage integration TODO)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

desktop/src-tauri/src/intelligence_hooks.rs

@@ -58,6 +58,26 @@ pub async fn post_conversation_hook(
     crate::intelligence::heartbeat::record_interaction(agent_id);
     debug!("[intelligence_hooks] Recorded interaction for agent: {}", agent_id);
 
+    // Step 1.5: Detect personality adjustment signals
+    if !_user_message.is_empty() {
+        let config = crate::intelligence::personality_detector::load_personality_config(agent_id);
+        let adjustments = crate::intelligence::personality_detector::detect_personality_signals(
+            _user_message, &config,
+        );
+        if !adjustments.is_empty() {
+            let new_config = crate::intelligence::personality_detector::apply_personality_adjustments(
+                &config, &adjustments,
+            );
+            crate::intelligence::personality_detector::save_personality_config(agent_id, &new_config);
+            for adj in &adjustments {
+                debug!(
+                    "[intelligence_hooks] Personality adjusted: {} {} -> {} (trigger: {})",
+                    adj.dimension, adj.from_value, adj.to_value, adj.trigger
+                );
+            }
+        }
+    }
+
     // Step 2: Record conversation for reflection
     let mut engine = reflection_state.lock().await;