Deploy console: real progress bar for image pulls (0.39.0)

Compose is now run with `--progress json` (probed once, falls back to the
plain text stream on older compose/agents). The console folds the event
stream into a weighted progress bar — download bytes per layer, then
container create/start — with a per-image bar and a byte/layer counter,
and renders the raw output one line per layer (updated in place) instead
of a wall of scrolling text.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "stackpilot-frontend",
   "private": true,
-  "version": "0.38.3",
+  "version": "0.39.0",
   "type": "module",
   "scripts": {
     "dev": "vite",