Switch from email-based OIDC matching to the stable `sub` claim.
Existing users are migrated by email on first login, new users are
auto-enrolled from OIDC claims, and admin status is synced from the
IdP's groups claim. Also expose oidc_sub on the admin edit-user page.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Support config-driven choice between MySQL and SQLite via DB_DRIVER
constant, defaulting to MySQL for backward compatibility. All SQL
adaptation lives in Database.php (UDFs + query rewriting), so model
files need no changes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
SQLite: remove FK constraints, revert 0→null sentinel changes
The SQLite schema had FOREIGN KEY constraints that don't exist in the
MySQL schema. These forced a cascade of 0→null changes to satisfy FK
enforcement. Removing them keeps the two backends behaviorally consistent
and minimises the diff. Real SQLite compat fixes (UDFs, query rewriting,
rowCount→count, Router fixes, EditAlbum guard) are preserved.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
