feat: user personalization with Honcho-backed preferences

- WelcomeScreen: first-time name entry with cute onboarding
- identify WS message: sets user_id, loads saved prefs from Honcho
- set_preference WS message: saves scene/outfit/accessory to Honcho metadata
- Preferences auto-load on return visits via localStorage + Honcho peer meta
- Kira uses the user's name in greeting and prompts
- Backend: get/set preference methods in KiraMemory service
- Frontend: optimistic preference updates, synced to backend on change

backend/services/memory.py

@@ -178,6 +178,54 @@ class KiraMemory:
         except Exception as e:
             logger.warning(f"Failed to store Kira message: {e}")
 
+    # ─── User preferences (stored in Honcho peer metadata) ───
+
+    DEFAULT_PREFERENCES: dict[str, str] = {
+        "name": "",
+        "scene": "cozy-room",
+        "outfit": "cozy-hoodie",
+        "accessory": "",
+    }
+
+    def get_user_preferences(self, user_id: str) -> dict[str, str]:
+        """Load user preferences from Honcho peer metadata."""
+        if not self.enabled:
+            return dict(self.DEFAULT_PREFERENCES)
+
+        try:
+            peer = self._honcho.peer(user_id)
+            meta = peer.metadata or {}
+            prefs = dict(self.DEFAULT_PREFERENCES)
+            for key in prefs:
+                val = meta.get(key)
+                if val is not None:
+                    prefs[key] = str(val)
+            logger.info(f"Loaded preferences for {user_id}: {prefs}")
+            return prefs
+        except Exception as e:
+            logger.warning(f"Failed to load preferences: {e}")
+            return dict(self.DEFAULT_PREFERENCES)
+
+    def set_user_preference(
+        self, user_id: str, key: str, value: str
+    ) -> bool:
+        """Save a single user preference to Honcho peer metadata."""
+        if key not in self.DEFAULT_PREFERENCES:
+            logger.warning(f"Unknown preference key: {key}")
+            return False
+
+        try:
+            peer = self._honcho.peer(user_id)
+            # Merge with existing metadata
+            meta = dict(peer.metadata or {})
+            meta[key] = value
+            peer.set_metadata(meta)
+            logger.info(f"Saved preference {user_id}.{key} = {value}")
+            return True
+        except Exception as e:
+            logger.warning(f"Failed to save preference: {e}")
+            return False
+
 
 # Singleton instance for the app
 kira_memory = KiraMemory()