Critical fixes:
- Move svc creation in router.go above MountInviteRoutes/MountChannelRoutes
(was used before definition — compile error)
- Restore hasChannelPermREST in channel_handler.go for upload_handler.go
(was removed but still referenced — compile error)
Permission cache invalidation:
- Add PermissionInvalidator interface to admin package
- Wire through NewHandler → NewAdminAPI → handlePatchUser
- Call InvalidateUser(userID) after role changes in admin panel
- Update all admin test files to pass nil as new parameter
Also clarifies WithTx documentation for SQLite single-writer semantics.
https://claude.ai/code/session_01CBFF3r84ywkJRWwuqw8zD8