fix(agent): quote DSN values and drop deprecated testcontainers import

agent/tests/test_db.py

@@ -37,3 +37,25 @@ def test_sync_runs_rejects_bad_status(cfg):
             "INSERT INTO sync_runs (connector, started_at, status)"
             " VALUES ('x', now(), 'bogus')"
         )
+
+
+def test_agent_dsn_escapes_password_with_space_and_quote():
+    import psycopg
+    from agent.config import AgentConfig
+    from agent.db import agent_dsn
+
+    cfg = AgentConfig(
+        db_host="localhost",
+        db_port=5432,
+        db_user="testuser",
+        db_password="pa ss'word",  # password with space and single quote
+        agent_db_name="testdb",
+        firefly_url="http://firefly.test",
+        firefly_token="test-token",
+        heartbeat_interval_minutes=60,
+    )
+
+    dsn = agent_dsn(cfg)
+    # Parse DSN and verify password is preserved correctly
+    parsed = psycopg.conninfo.conninfo_to_dict(dsn)
+    assert parsed["password"] == "pa ss'word"