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/000030_fix_oauth_tokens_schema_drift.up.sql

@@ -0,0 +1,16 @@
+BEGIN;
+
+-- Reconciles oauth_tokens with the schema the application code actually
+-- expects. Neither of these two changes was ever committed as a migration
+-- despite being applied by hand at some point - see the "claims" column
+-- below, which no application code reads or writes.
+
+ALTER TABLE oauth_tokens
+	DROP COLUMN claims;
+
+ALTER TABLE oauth_tokens
+	ALTER COLUMN id_token_custom_claims_updated_at
+	TYPE TIMESTAMPTZ
+	USING id_token_custom_claims_updated_at::TIMESTAMPTZ;
+
+COMMIT;