Fix polling to use 24-hour window instead of resume feature

- Polling now always collects posts from last 24 hours
- Removes resume feature that created too-narrow time windows
- Fixes issue where polls returned 0 posts due to minutes-wide ranges

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

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

polling_service.py

@@ -145,15 +145,20 @@ class PollingService:
         Collect data from a source.
         Wraps the existing data_collection.py functionality.
         """
-        from data_collection import ensure_directories, load_index, save_index, calculate_date_range, load_state, save_state
+        from data_collection import ensure_directories, load_index, save_index, load_state, save_state
+        from datetime import datetime, timedelta
 
         # Setup directories and load state
         dirs = ensure_directories(self.storage_dir)
         index = load_index(self.storage_dir)
         state = load_state(self.storage_dir)
 
-        # Calculate date range (collect last 1 day)
-        start_iso, end_iso = calculate_date_range(1, state)
+        # Calculate date range - always use last 24 hours for polling
+        # Don't use the resume feature as it can create too narrow windows
+        end_date = datetime.now()
+        start_date = end_date - timedelta(hours=24)
+        start_iso = start_date.isoformat()
+        end_iso = end_date.isoformat()
 
         try:
             # Call the existing collect_platform function