Remove file-based caching of OAuth client credentials and implement automatic
client lifecycle management for test fixtures.
Changes:
- Add RFC 7592 client deletion function in auth/client_registration.py
- Remove cache_file parameter from _create_oauth_client_with_scopes helper
- Update all OAuth credential fixtures to use yield/finalizer pattern
- Add automatic client cleanup at end of test session (best-effort)
- Remove persistent .nextcloud_oauth_*.json cache files
Benefits:
- No persistent cache files cluttering repository
- Fresh OAuth clients created for each test session via DCR
- Automatic cleanup attempts (RFC 7592 DELETE endpoint)
- Cleaner test environment with proper fixture lifecycle
Note: Client deletion may fail due to Nextcloud authentication middleware
(logged as warning). The key improvement is removing persistent cache files.
OAuth clients may accumulate in Nextcloud but can be cleaned manually.
Chris Coutinho