Cascade deletes in DB schema

Inline foreign key definitions in DB schema

Turn on SQLite foreign keys

Set SQLite concurrency options

Use context in DB.upgrade

Delete authorization codes on client revocation

Add support for refresh tokens

Closes: https://todo.sr.ht/~emersion/sinwon/21

Add dark theme

Co-authored-by: ~ckyb
Closes: https://todo.sr.ht/~emersion/sinwon/28

Add DB migration infrastructure

Add basic stylesheet

Add server name config directive

References: https://todo.sr.ht/~emersion/sinwon/24

Fix admin ignored in DB.StoreUser

Fix root user missing admin flag

readme: add usage

Push cancel buttons to the right

Add button to rotate client secret

Check redirect URI param in token endpoint

Fix outdated login cookie name

Drop outdated TODO

Add server issuer information

Closes: https://todo.sr.ht/~emersion/sinwon/11