fix(ci): set DATABASE_URL and AUTH_SECRET for Prisma in CI

Prisma requires DATABASE_URL even for client generation.
The CI workflow cloned to a fresh temp dir has no .env file,
so these must be provided as env vars.

.gitea/workflows/ci.yaml

@@ -30,6 +30,8 @@ jobs:
           git checkout -f "${REF}"
 
           export SKIP_ENV_VALIDATION=1
+          export DATABASE_URL="mysql://test:test@localhost:3306/test?charset=utf8mb4"
+          export AUTH_SECRET="ci-test-secret-key-that-is-long-enough"
           export ARGON2_MEMORY_SIZE=1024
           export ARGON2_ITERATIONS=1
           export BCRYPT_ROUNDS=4