Claude-assisted improvements (untested)

- dev auth flow (side-step OAuth)
- db event processing integration tests
- dev scripts (eg Makefile)
- db / test db migration setup scripts.

database_migrations/000010_oauth_login_states.up.sql

@@ -1,6 +1,6 @@
 CREATE TABLE oauth_login_states (
 	state 			BYTEA 	NOT NULL,
-	expiration 		TIMESTAMPTZ NOT NULL DEFAULT (NOW() + 10 'minute'),
+	expiration 		TIMESTAMPTZ NOT NULL DEFAULT (NOW() + '10 minutes'::interval),
 
 	PRIMARY KEY (state)
 );