ci: add GUI build, dev branch trigger, crash restart hard failure

- CI now triggers on gui/** paths and dev branch pushes/PRs
- GUI build step added to CI matrix
- systemd crash restart failure is now a hard error (was warning)

Author: lidge-jun

.github/workflows/ci.yml

@@ -2,22 +2,24 @@ name: Cross-platform CI
 
 on:
   pull_request:
-    branches: [main]
+    branches: [main, dev]
     paths:
       - "src/**"
       - "tests/**"
       - "scripts/**"
+      - "gui/**"
       - "package.json"
       - "bun.lock"
       - "tsconfig.json"
       - ".github/workflows/ci.yml"
       - ".github/workflows/release.yml"
   push:
-    branches: [main]
+    branches: [main, dev]
     paths:
       - "src/**"
       - "tests/**"
       - "scripts/**"
+      - "gui/**"
       - "package.json"
       - "bun.lock"
       - "tsconfig.json"
@@ -62,5 +64,8 @@ jobs:
       - name: Check release helper syntax
         run: bun build scripts/release.ts --target=bun --outdir=.tmp/ci-release-script-check
 
+      - name: GUI build
+        run: cd gui && bun run build
+
       - name: CLI help smoke
         run: bun run src/cli.ts help

.github/workflows/service-lifecycle.yml

@@ -65,7 +65,8 @@ jobs:
             if systemctl --user is-active opencodex-proxy 2>/dev/null; then
               echo "✅ Service restarted after crash"
             else
-              echo "⚠️  Service did not restart (may need lingering)"
+              echo "❌ Service did not restart after crash"
+              exit 1
             fi
           fi