feat(preview): real preview environments — clone, deploy, TTL, promote (#67)

Preview environments were bookkeeping only: a fabricated deployment row
marked "running" and a fake *.preview.containr.local URL. Now a preview
is a real service clone — full config copy (source, env, volumes, access),
git_branch pinned to the requested branch, its own preview hostname under
the clone's node default domain, and a real deployment through the queue.

- cloneServiceRow extracted from handleCloneService for reuse
- preview_environments.preview_service_id links to the clone
- minute sweeper: expires past-TTL previews (removes clone runtime + row)
  and syncs preview status from the clone's live service status
- delete/cleanup paths tear the clone down, not just the row
- promote redeploys the SOURCE service at the preview branch and retires
  the clone — a real deployment, not a pending stub

Verified live: create → clone → deploy → running container; TTL expiry →
clone + container gone; promote → real deploy on the source, preview
stopped. Unit test covers the DNS-safe clone naming.

Generated with [Devin](https://devin.ai)

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/src/generated/api-types.ts

@@ -12495,6 +12495,11 @@ export interface components {
             project_id?: string;
             /** Format: uuid */
             service_id?: string;
+            /**
+             * Format: uuid
+             * @description The cloned service the preview actually deploys; its live status drives the preview status.
+             */
+            preview_service_id?: string;
             branch_name?: string;
             pr_number?: number;
             /** @description Generated name, e.g. preview-{branch}-{ts} */