fix: align default limits and parameter names to spec

- get_recent_memories: limit default 10 → 5
- get_memories_by_topics: limit default 10 → 5
- prune_excess_memories: rename 'cap' → 'max_memories'

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

utils/database.py

@@ -548,7 +548,7 @@ class Database:
         finally:
             conn.close()
 
-    async def get_recent_memories(self, user_id: int, limit: int = 10) -> list[dict]:
+    async def get_recent_memories(self, user_id: int, limit: int = 5) -> list[dict]:
         """Get the N most recent non-expired memories for a user."""
         if not self._available:
             return []
@@ -583,7 +583,7 @@ class Database:
         finally:
             conn.close()
 
-    async def get_memories_by_topics(self, user_id: int, topic_keywords: list[str], limit: int = 10) -> list[dict]:
+    async def get_memories_by_topics(self, user_id: int, topic_keywords: list[str], limit: int = 5) -> list[dict]:
         """Get non-expired memories matching any of the given topic keywords via LIKE."""
         if not self._available:
             return []
@@ -655,18 +655,18 @@ class Database:
         finally:
             conn.close()
 
-    async def prune_excess_memories(self, user_id: int, cap: int = 50) -> int:
+    async def prune_excess_memories(self, user_id: int, max_memories: int = 50) -> int:
         """Delete excess memories for a user beyond the cap, keeping high importance and newest first.
         Returns count deleted."""
         if not self._available:
             return 0
         try:
-            return await asyncio.to_thread(self._prune_excess_memories_sync, user_id, cap)
+            return await asyncio.to_thread(self._prune_excess_memories_sync, user_id, max_memories)
         except Exception:
             logger.exception("Failed to prune excess memories")
             return 0
 
-    def _prune_excess_memories_sync(self, user_id, cap) -> int:
+    def _prune_excess_memories_sync(self, user_id, max_memories) -> int:
         conn = self._connect()
         try:
             cursor = conn.cursor()
@@ -689,7 +689,7 @@ class Database:
                        ) ranked
                        WHERE rn > ?
                    )""",
-                user_id, cap,
+                user_id, max_memories,
             )
             count = cursor.rowcount
             cursor.close()