added fix for deployment race condition

CONTEXT.md

@@ -7,7 +7,7 @@
 >
 > Ask Claude Code: "Please update CONTEXT.md with what we did today"
 
-Last updated: 2026-02-14 (session 3)
+Last updated: 2026-02-14 (session 4)
 
 ---
 
@@ -28,7 +28,17 @@ Last updated: 2026-02-14 (session 3)
 - **Running on:** demo-felhom (N100 mini PC) at 192.168.0.162:8080
 - **All Phase 1 features working:** deploy, start/stop/restart/update, logs, health-aware states, auth
 
-### What was just completed (2026-02-14 session 3)
+### What was just completed (2026-02-14 session 4)
+- **Fixed deploy race condition** in `internal/stacks/deploy.go`:
+  - In-memory `Deployed` flag now set BEFORE `docker compose up -d` (compose up can take 30-60s for image pulls)
+  - On failure: both in-memory state and disk (app.yaml) are reverted
+  - Eliminates stale "Telepítés" button during long compose operations
+- **Added `checkBeforeDeploy()` JS guard** in `internal/web/templates.go`:
+  - Telepítés buttons on Vezérlőpult and Alkalmazások pages now fetch live state from `/api/stacks/{name}` before navigating
+  - If app is already deployed (e.g., another tab deployed it), shows alert and reloads page instead of navigating to deploy form
+  - Catches stale UI state gracefully
+
+### Previously completed (2026-02-14 session 3)
 - **Enhanced debug logging** across all stack operations in `internal/stacks/`:
   - **Operation timing**: All stack ops (start, stop, restart, update, deploy) now log elapsed time
   - **Post-start container state check**: Async goroutine after start/restart/update/deploy
@@ -179,7 +189,7 @@ Last updated: 2026-02-14 (session 3)
 - Go maps have random iteration order — always sort slices before displaying
 - Docker `.State`="running" doesn't mean healthy — check `.Status` for "(health: starting)" / "(unhealthy)"
 - Paperless-ngx needs `PAPERLESS_OCR_LANGUAGES` (plural) to install language packs, `PAPERLESS_OCR_LANGUAGE` (singular) to select
-- After deploying a stack, update the in-memory Deployed flag immediately — RefreshStatus() only reads docker ps
+- In-memory Deployed flag must be set BEFORE `docker compose up -d` (not after) — compose can take 30-60s for image pulls, during which the UI would show a stale "Telepítés" button
 - Cloudflare Tunnel handles *.demo-felhom.eu → Traefik handles Host()-based routing to containers
 - BIOS "AC Power Recovery" must be enabled on N100 for auto-restart after power outage
 - `docker compose up -d` returns exit 0 even when containers immediately crash-loop — need post-start status check to detect this