fix: use real DATABASE_URL from .env for migrations in deploy workflow

The deploy job was overwriting DATABASE_URL with a placeholder for
prisma:generate, but this persisted when db:migrate ran later, causing
ER_ACCESS_DENIED_ERROR. Since the stage directory already symlinks to
the live .env, the real DATABASE_URL is available without override.

.gitea/workflows/deploy.yaml

@@ -336,8 +336,8 @@ jobs:
           echo "STAGE DATABASE_POOL_SIZE=${DATABASE_POOL_SIZE}"
 
            pnpm install --frozen-lockfile
-          export DATABASE_URL="${DEPLOY_DATABASE_URL:-mysql://placeholder:please@localhost/placeholder}"
-          # prisma generate does not need a live DB connection.
+           # Stage symlinks to live .env, so DATABASE_URL is already the real value.
+           # prisma generate only needs the URL for client generation — no live DB connection.
            pnpm prisma:generate
           export BCRYPT_ROUNDS=4
           pnpm typecheck