/api/activity and /api/activity-feed were never registered in app.py —
both files existed but neither route was reachable (confirmed 404 on VPS).
Register both so Timeline and gamification feeds can consume them.
Adds source_channel to /api/activity payload (both PR rows and audit
events — audit rows return null since they aren't tied to a specific PR).
Migration v22 already populated prs.source_channel on VPS with enum:
telegram=2340, agent=698, maintenance=102, unknown=11, github=1.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>