fix: resolve ruff lint errors (unused imports and variables)

src/claude_memory/api/app.py

@@ -2,7 +2,6 @@
 
 import logging
 from contextlib import asynccontextmanager
-from datetime import datetime, timezone
 from typing import Optional
 
 from fastapi import Depends, FastAPI, HTTPException

tests/test_credential_detector.py

@@ -1,9 +1,7 @@
 """Tests for credential detection and redaction."""
 
-import pytest
 
 from claude_memory.credential_detector import (
-    DetectedCredential,
     detect_credentials,
     is_sensitive,
     redact_credentials,

tests/test_crypto.py

@@ -1,7 +1,5 @@
 """Tests for AES-256-GCM encryption module."""
 
-import hashlib
-import os
 
 import pytest
 

tests/test_mcp_server.py

@@ -13,7 +13,7 @@ os.environ.pop("CLAUDE_MEMORY_API_KEY", None)
 # Add src to path so we can import without installing
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "src"))
 
-from claude_memory.mcp_server import MemoryServer, TOOLS, SERVER_NAME, SERVER_VERSION, PROTOCOL_VERSION
+from claude_memory.mcp_server import MemoryServer, SERVER_NAME, SERVER_VERSION, PROTOCOL_VERSION
 
 
 @pytest.fixture

tests/test_vault_client.py

@@ -1,7 +1,6 @@
 """Tests for Vault KV v2 client with mocked urllib."""
 
 import json
-import os
 from io import BytesIO
 from unittest.mock import MagicMock, mock_open, patch
 
@@ -100,7 +99,7 @@ class TestVaultWrite:
         mock_urlopen.return_value = mock_response
 
         client = VaultClient()
-        result = client.write("myapp/config", {"key": "value"})
+        client.write("myapp/config", {"key": "value"})
 
         # Verify the request was made with correct data
         call_args = mock_urlopen.call_args