feat: add memory_facts DB helpers

Implement four async DB-helper functions for memory_facts table:
- insert_memory_fact(user_id, content) -> int
- search_memory_facts(query) -> list
- delete_memory_fact(fact_id) -> None
- get_all_memory_facts() -> list

Add test_memory.py with 4 passing tests for these helpers.
All tests pass with mocked db_query.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iZMEPk2Kt1UC96Lo9bC5w

Claude outputs/tests/test_memory.py

@@ -0,0 +1,56 @@
+import os
+import sys
+from unittest.mock import AsyncMock, patch, MagicMock
+
+# Mock psycopg2 before importing main
+sys.modules["psycopg2"] = MagicMock()
+sys.modules["psycopg2.pool"] = MagicMock()
+sys.modules["psycopg2.extras"] = MagicMock()
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+import pytest
+
+import main
+
+
+@pytest.mark.asyncio
+async def test_insert_memory_fact_returns_new_id():
+    with patch.object(main, "db_query", new=AsyncMock(return_value={"id": 42})) as mock_query:
+        fact_id = await main.insert_memory_fact(1, "Mag lieber Tee als Kaffee")
+
+    assert fact_id == 42
+    args, kwargs = mock_query.call_args
+    assert "INSERT INTO memory_facts" in args[0]
+    assert args[1] == (1, "Mag lieber Tee als Kaffee")
+
+
+@pytest.mark.asyncio
+async def test_search_memory_facts_uses_ilike():
+    rows = [{"id": 1, "content": "Hund heisst Bruno"}]
+    with patch.object(main, "db_query", new=AsyncMock(return_value=rows)) as mock_query:
+        result = await main.search_memory_facts("Bruno")
+
+    assert result == rows
+    args, kwargs = mock_query.call_args
+    assert "ILIKE" in args[0]
+    assert args[1] == ("%Bruno%",)
+
+
+@pytest.mark.asyncio
+async def test_delete_memory_fact_deletes_by_id():
+    with patch.object(main, "db_query", new=AsyncMock(return_value=None)) as mock_query:
+        await main.delete_memory_fact(7)
+
+    args, kwargs = mock_query.call_args
+    assert "DELETE FROM memory_facts" in args[0]
+    assert args[1] == (7,)
+
+
+@pytest.mark.asyncio
+async def test_get_all_memory_facts_returns_rows():
+    rows = [{"id": 1, "content": "A"}, {"id": 2, "content": "B"}]
+    with patch.object(main, "db_query", new=AsyncMock(return_value=rows)):
+        result = await main.get_all_memory_facts()
+
+    assert result == rows