fix(logging): replace structlog with stdlib logging to prevent broken pipe crashes

structlog fails with BrokenPipeError when stdout is redirected (e.g., background
processes, Docker logs). Replace all structlog.get_logger() calls with
logging.getLogger() and convert keyword-style log calls to %-format strings.

Also removes stale Docs/tasks.md (2028 lines) and updates Robot Framework
tests to match current API behavior.

src/server/utils/error_tracking.py

@@ -74,13 +74,8 @@ class ErrorTracker:
             self.error_history = self.error_history[-self.max_history_size:]
 
         logger.info(
-            f"Error tracked: {error_id}",
-            extra={
-                "error_id": error_id,
-                "error_type": error_type,
-                "status_code": status_code,
-                "request_path": request_path,
-            },
+            "Error tracked error_id=%s error_type=%s status_code=%s request_path=%s",
+            error_id, error_type, status_code, request_path,
         )
 
         return error_id