The twelve feed methods (subscription CRUD, activity, errors, statistics, preview and item formatting) and the two module helpers they use move from app.py into modules/web_viewer/feeds.py; BotDataViewer inherits the mixin, so every method stays on the viewer for routes and tests. Method bodies are unchanged apart from dropping function-local 'import sqlite3' lines the module import now covers, and _validate_feed_interval's annotation (object to Any, for mypy, which now checks this module). app.py keeps every name it imported for them so modules.web_viewer.app.<name> still resolves. The two tests that patched create_safe_requests_session and safe_requests_request to steer _preview_feed_items now patch them where the method lives; the SafeUrlPolicy.validate patches target the shared class and are unchanged. app.py drops to about 8,200 lines.
