Add managed databases and services with billing-aligned upgrades.

Introduce product types for managed PostgreSQL, Redis, and RabbitMQ with a dedicated dashboard, Helm-only deploy pipeline, external access, snapshots with progress, and prorated resource or storage upgrades matching application billing rules. PVCs use an expandable StorageClass with automatic migration when legacy disks cannot resize in place.

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

backend/migrations/017_snapshot_progress.sql

@@ -0,0 +1,2 @@
+-- Snapshot creation progress (0–100) for UI feedback during DB dumps
+ALTER TABLE snapshots ADD COLUMN IF NOT EXISTS progress INT NOT NULL DEFAULT 0;