Fix community settings page 500 error

- Added comprehensive error handling for platform config loading
- Added validation for collection_targets structure
- Added defensive programming for community data processing
- Added logging for debugging community list building
- Prevents crashes when config files are missing or malformed

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

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

app.py

@@ -1399,17 +1399,38 @@ def settings_communities():
     # Get available communities from platform config and collection targets
     available_communities = []
 
-    # Load platform configuration
+    # Load platform configuration with error handling
+    try:
         platform_config = load_platform_config()
+        if not platform_config:
+            platform_config = {"platforms": {}, "collection_targets": []}
+    except Exception as e:
+        logger.error(f"Error loading platform config: {e}")
+        platform_config = {"platforms": {}, "collection_targets": []}
 
     # Get enabled communities from collection_targets (what's actually being crawled)
     enabled_communities = set()
+    try:
         for target in platform_config.get('collection_targets', []):
+            if 'platform' in target and 'community' in target:
                 enabled_communities.add((target['platform'], target['community']))
+    except Exception as e:
+        logger.error(f"Error processing collection_targets: {e}")
     
     # Build community list from platform config for communities that are enabled
+    try:
         for platform_name, platform_info in platform_config.get('platforms', {}).items():
-        for community_info in platform_info.get('communities', []):
+            if not isinstance(platform_info, dict):
+                continue
+            communities = platform_info.get('communities', [])
+            if not isinstance(communities, list):
+                continue
+
+            for community_info in communities:
+                try:
+                    if not isinstance(community_info, dict):
+                        continue
+
                     # Only include communities that are in collection_targets
                     if (platform_name, community_info['id']) in enabled_communities:
                         available_communities.append({
@@ -1420,6 +1441,13 @@ def settings_communities():
                             'icon': community_info.get('icon', platform_info.get('icon', '📄')),
                             'description': community_info.get('description', '')
                         })
+                except Exception as e:
+                    logger.error(f"Error processing community {community_info}: {e}")
+                    continue
+    except Exception as e:
+        logger.error(f"Error building community list: {e}")
+
+    logger.info(f"Found {len(available_communities)} available communities")
 
     return render_template('settings_communities.html',
                          user=current_user,