fix(contacts): sync device↔DB contacts, restore contact cache

- get_contacts_with_last_seen() reads from mc.contacts (device firmware)
  instead of DB, so /api/contacts/detailed returns only device contacts
- _sync_contacts_to_db() now bidirectional: downgrades stale 'device'
  contacts to 'advert' (cache-only) when not on device anymore
- delete_contact() sets source='advert' (cache) instead of 'deleted',
  keeping contacts visible in @mentions and cache filter
- get_contacts() returns all contacts (no 'deleted' filter needed)

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

app/database.py

@@ -116,7 +116,7 @@ class Database:
     def get_contacts(self) -> List[Dict]:
         with self._connect() as conn:
             rows = conn.execute(
-                "SELECT * FROM contacts WHERE source != 'deleted' ORDER BY last_seen DESC"
+                "SELECT * FROM contacts ORDER BY last_seen DESC"
             ).fetchall()
             return [dict(r) for r in rows]
 
@@ -147,18 +147,33 @@ class Database:
             return dict(row) if row else None
 
     def delete_contact(self, public_key: str) -> bool:
-        """Soft-delete: mark as 'deleted' instead of removing.
+        """Move contact to cache (source='advert') instead of deleting.
 
-        Keeps the row so FK references in direct_messages stay intact.
-        upsert_contact() overwrites source on re-add, auto-undeleting.
+        Contact stays visible in cache and @mentions but not in device list.
+        upsert_contact() overwrites source on re-add (back to 'device').
         """
         with self._connect() as conn:
             cursor = conn.execute(
-                "UPDATE contacts SET source = 'deleted', lastmod = datetime('now') WHERE public_key = ?",
+                "UPDATE contacts SET source = 'advert', lastmod = datetime('now') WHERE public_key = ?",
                 (public_key.lower(),)
             )
             return cursor.rowcount > 0
 
+    def downgrade_stale_device_contacts(self, active_device_keys: set) -> int:
+        """Downgrade contacts marked 'device' that are no longer on the device."""
+        with self._connect() as conn:
+            all_device = conn.execute(
+                "SELECT public_key FROM contacts WHERE source = 'device'"
+            ).fetchall()
+            stale_keys = [r['public_key'] for r in all_device
+                          if r['public_key'] not in active_device_keys]
+            if stale_keys:
+                conn.executemany(
+                    "UPDATE contacts SET source = 'advert', lastmod = datetime('now') WHERE public_key = ?",
+                    [(k,) for k in stale_keys]
+                )
+            return len(stale_keys)
+
     def set_contact_protected(self, public_key: str, protected: bool) -> bool:
         with self._connect() as conn:
             cursor = conn.execute(

app/device_manager.py

@@ -268,11 +268,15 @@ class DeviceManager:
             logger.debug(f"Subscribed to {event_type.value}")
 
     def _sync_contacts_to_db(self):
-        """Sync device contacts to database."""
+        """Sync device contacts to database (bidirectional).
+
+        - Upserts device contacts with source='device'
+        - Downgrades DB contacts marked 'device' that are no longer on device to 'advert'
+        """
         if not self.mc or not self.mc.contacts:
             return
 
-        count = 0
+        device_keys = set()
         for pubkey, contact in self.mc.contacts.items():
             # last_advert from meshcore is Unix timestamp (int) or None
             last_adv = contact.get('last_advert')
@@ -290,8 +294,13 @@ class DeviceManager:
                 adv_lon=contact.get('adv_lon'),
                 source='device',
             )
-            count += 1
-        logger.info(f"Synced {count} contacts from device to database")
+            device_keys.add(pubkey.lower())
+
+        # Downgrade stale 'device' contacts to 'advert' (cache-only)
+        stale = self.db.downgrade_stale_device_contacts(device_keys)
+        if stale:
+            logger.info(f"Downgraded {stale} stale device contacts to cache")
+        logger.info(f"Synced {len(device_keys)} contacts from device to database")
 
     def execute(self, coro, timeout: float = 30) -> Any:
         """

app/meshcore/cli.py

@@ -147,24 +147,25 @@ def _parse_last_advert(value) -> int:
 
 
 def get_contacts_with_last_seen() -> Tuple[bool, Dict[str, Dict], str]:
-    """Get contacts with last_advert timestamps from DB."""
+    """Get contacts actually on the device firmware (from mc.contacts)."""
     try:
         dm = _get_dm()
-        contacts = dm.db.get_contacts()
+        if not dm.mc or not dm.mc.contacts:
+            return True, {}, ""
         contacts_dict = {}
-        for c in contacts:
-            pk = c.get('public_key', '')
+        for pk, contact in dm.mc.contacts.items():
+            last_adv = contact.get('last_advert')
             contacts_dict[pk] = {
                 'public_key': pk,
-                'type': c.get('type', 1),
-                'flags': c.get('flags', 0),
-                'out_path_len': c.get('out_path_len', -1),
-                'out_path': c.get('out_path', ''),
-                'adv_name': c.get('name', ''),
-                'last_advert': _parse_last_advert(c.get('last_advert')),
-                'adv_lat': c.get('adv_lat', 0.0),
-                'adv_lon': c.get('adv_lon', 0.0),
-                'lastmod': c.get('lastmod', ''),
+                'type': contact.get('type', 1),
+                'flags': contact.get('flags', 0),
+                'out_path_len': contact.get('out_path_len', -1),
+                'out_path': contact.get('out_path', ''),
+                'adv_name': contact.get('adv_name', contact.get('name', '')),
+                'last_advert': int(last_adv) if last_adv and isinstance(last_adv, (int, float)) and last_adv > 0 else 0,
+                'adv_lat': contact.get('adv_lat', 0.0),
+                'adv_lon': contact.get('adv_lon', 0.0),
+                'lastmod': '',
             }
         return True, contacts_dict, ""
     except Exception as e: