Add optional service pricing matrix and fix admin catalog save.

Users pick per-service CPU/memory/storage at deploy; admins manage unit rates and deploy defaults. PATCH sends only fields accepted by the pricing-catalog DTO.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/migrations/008_application_optional_service_resources.sql

@@ -0,0 +1,4 @@
+-- Per-deploy optional service resource limits (user-chosen, like application CPU/RAM/storage)
+
+ALTER TABLE applications
+  ADD COLUMN IF NOT EXISTS optional_service_resources JSONB;