fix: await semantic memory initialization

Sync async SemanticMemory initialization compatibility fix.

memory/semantic.py

@@ -127,7 +127,7 @@ class SemanticMemory:
         except Exception:
             return None
 
-    def init(self):
+    async def init(self):
         if self._sb is None:
             self._sb = self._try_supabase()
         if self._sb: