fix: add fetchall() and fetchone() helper methods to DatabaseManager

- Code was calling db.fetchall() and db.fetchone() but these methods didn't exist
- Add helper methods that execute query and return results
- Fixes template loading and other database operations

core/database.py

@@ -152,6 +152,34 @@ class DatabaseManager:
         conn = self.get_connection()
         return conn.executemany(query, parameters)
     
+    def fetchall(self, query: str, parameters: tuple = ()) -> List[sqlite3.Row]:
+        """
+        Execute query and fetch all results.
+        
+        Args:
+            query: SQL query string
+            parameters: Query parameters
+            
+        Returns:
+            List of row objects
+        """
+        cursor = self.execute(query, parameters)
+        return cursor.fetchall()
+    
+    def fetchone(self, query: str, parameters: tuple = ()) -> Optional[sqlite3.Row]:
+        """
+        Execute query and fetch first result.
+        
+        Args:
+            query: SQL query string
+            parameters: Query parameters
+            
+        Returns:
+            Single row or None
+        """
+        cursor = self.execute(query, parameters)
+        return cursor.fetchone()
+    
     def commit(self) -> None:
         """Commit current transaction."""
         if self._connection: