Fix 3 critical issues identified in repository review

**Critical Fixes:**

1. **Fixed Error Hierarchy** (wikijs/exceptions.py)
   - ConnectionError and TimeoutError now properly inherit from APIError
   - Ensures consistent exception handling across the SDK
   - Added proper __init__ methods with status_code=None

2. **Fixed test_connection Method** (wikijs/client.py)
   - Changed from basic HTTP GET to proper GraphQL query validation
   - Now uses query { site { title } } to validate API connectivity
   - Provides better error messages for authentication failures
   - Validates both connectivity AND API access

3. **Implemented JWT Token Refresh** (wikijs/auth/jwt.py)
   - Added base_url parameter to JWTAuth class
   - Implemented complete refresh() method with HTTP request to /api/auth/refresh
   - Handles token, refresh token, and expiration updates
   - Proper error handling for network failures and auth errors

**Bonus Fixes:**
- Dynamic user agent version (uses __version__ from version.py instead of hardcoded)
- Updated all JWT tests to include required base_url parameter
- Updated test mocks to match new GraphQL-based test_connection

**Test Results:**
- All 231 tests passing ✅
- Test coverage: 91.64% (target: 85%) ✅
- No test failures or errors

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

wikijs/exceptions.py

@@ -72,13 +72,19 @@ class RateLimitError(ClientError):
         self.retry_after = retry_after
 
 
-class ConnectionError(WikiJSException):
+class ConnectionError(APIError):
     """Raised when there's a connection issue."""
 
+    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None) -> None:
+        super().__init__(message, status_code=None, response=None, details=details)
 
-class TimeoutError(WikiJSException):
+
+class TimeoutError(APIError):
     """Raised when a request times out."""
 
+    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None) -> None:
+        super().__init__(message, status_code=None, response=None, details=details)
+
 
 def create_api_error(status_code: int, message: str, response: Any = None) -> APIError:
     """Create appropriate API error based on status code.