Drizzle schema pro auth (users, sessions, oauth_accounts, password_resets)

Hotovo

Auth potreboval persistent storage. Drizzle schema definuje 4 tabulky (users, sessions, oauth_accounts s composite PK, password_resets) vcetne FK cascade a indexu. Tabulky pro Sprint 002 jsou pridane preventivne aby nebyla druha migrace. Migrace aplikovana lokalne.