feat: badge versione build in GUI + build.sh con auto-bump

- VERSION (1.0.0) + build.sh: bump patch/minor/major e deploy via docker compose
- Dockerfile: ARG/ENV APP_VERSION + BUILD_TIME (iniettati come build-arg)
- version.build_info(): env in Docker, fallback file VERSION + '(local)' in dev
- GET /api/version; badge #appVersionPill nell'header (tooltip = build time)
- test_version.py: env vs fallback

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/index.html

@@ -20,6 +20,7 @@
   </nav>
   <div class="status-strip" id="statusStrip"></div>
   <span class="active-robot-pill" id="activeRobotPill" title="Robot attualmente collegato">robot: —</span>
+  <span class="active-robot-pill" id="appVersionPill" title="versione build">V—</span>
 </header>
 
 <main>