FastAPI was matching /stats as a vendor_id (expecting int), causing 422 error.
Move /stats and /billing/history endpoints BEFORE /{vendor_id} so they take precedence.
Route order now:
1. /tiers/* - tier management
2. / - list subscriptions
3. /stats - statistics (before /{vendor_id})
4. /billing/history - billing history (before /{vendor_id})
5. /{vendor_id} - vendor detail endpoints (catch-all for ints)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>