fix: Remove tmpfs from PostgreSQL service (not allowed by Woodpecker)

Woodpecker CI doesn't allow tmpfs due to trust level restrictions.
The service is ephemeral anyway - data is auto-cleaned after each pipeline run.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.woodpecker.yml

@@ -21,8 +21,6 @@ services:
       POSTGRES_DB: test_db
       POSTGRES_USER: test_user
       POSTGRES_PASSWORD: test_password
-    tmpfs:
-      - /var/lib/postgresql/data
 
 steps:
   install: