feat(companion): enhance contact capacity management and bridge settings

- Introduced `CompanionContactCapacityError` to handle cases where persisted contacts exceed configured limits.
- Added utility functions for parsing companion bridge settings and validating contact capacity.
- Updated `RepeaterDaemon` to check contact capacity during companion loading and initialization.
- Enhanced API endpoints to validate companion settings and manage contact limits effectively.
- Implemented logging for bridge limits and errors related to contact capacity.

repeater/data_acquisition/sqlite_handler.py

@@ -2229,6 +2229,20 @@ class SQLiteHandler:
             return 0
 
     # Companion persistence methods
+    def companion_count_contacts(self, companion_hash: str) -> int:
+        """Return the number of persisted contacts for a companion."""
+        try:
+            with self._connect() as conn:
+                cursor = conn.execute(
+                    "SELECT COUNT(*) FROM companion_contacts WHERE companion_hash = ?",
+                    (companion_hash,),
+                )
+                row = cursor.fetchone()
+                return int(row[0]) if row else 0
+        except Exception as e:
+            logger.error(f"Failed to count companion contacts: {e}")
+            return 0
+
     def companion_load_contacts(self, companion_hash: str) -> List[Dict]:
         """Load contacts for a companion from storage."""
         try: