feat(deploy): async compose-up for instant UI feedback (v0.28.2)

Deploy API now returns immediately after validation + config save.
docker compose up -d runs in a background goroutine so the UI shows
progress during image pulls instead of blocking for 30-60s.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/README.md

@@ -142,8 +142,8 @@ The app catalog lives in a separate Git repository. The controller:
    - Hard block if `used_mb + new_request > usable_memory`
    - `CommittedMemory()` (declared sum) still used for soft overcommit warning only
    - Deploy page shows real memory usage bar (not declared reservations)
-5. Pre-generated secret values are submitted as hidden form inputs so the **same values** the user saw are saved to `app.yaml` (no silent re-generation on submit). Controller saves `app.yaml`, sets in-memory `Deployed` flag **before** `docker compose up -d` (avoids stale UI during slow image pulls), reverts on failure
-6. 3-step progress panel polls `GET /api/stacks/{name}` every 3s: config saved → containers starting → health check passed
+5. Pre-generated secret values are submitted as hidden form inputs so the **same values** the user saw are saved to `app.yaml` (no silent re-generation on submit). Controller saves `app.yaml`, sets in-memory `Deployed` + `Deploying` flags, then runs `docker compose up -d` **asynchronously** in a goroutine — API returns immediately so the UI switches to the progress panel without waiting for image pulls. On failure the goroutine reverts both disk and in-memory state and sets `DeployError`.
+6. 3-step progress panel polls `GET /api/stacks/{name}` every 3s: config saved → `deploying` (pulling images) → containers starting → health check passed. New `StateDeploying` state shown while compose-up is in progress (no containers yet).
 7. Post-deploy: locked fields (DB_PASSWORD, etc.) become read-only; the "Automatikusan generált értékek" section continues to show the saved values on the settings page
 
 #### App Info Pages
@@ -195,6 +195,7 @@ When app templates are updated (e.g., a new `APP_KEY` secret is added to `.felho
 |-------|-------|-------|---------|
 | Running + healthy | Green | "Fut" | All containers running and healthy |
 | Running + starting | Orange | "Indulas..." | Healthcheck not yet passed |
+| Deploying | Orange | "Telepítés..." | Compose up in progress (image pull, container creation) |
 | Running + unhealthy | Yellow | "Nem egeszseges" | Healthcheck failing |
 | Stopped/exited | Red | "Leallitva" | All containers stopped |
 | Restarting | Yellow | "Ujrainditas..." | Restart loop |