Add auto-incrementing version display to web UI footer

Exposes GET /version endpoint in the web container (reads APP_VERSION env var).
CI computes the version as 1.0.<git-commit-count> and passes it via --build-arg at build time.
Both index.html and cv-matcher/index.html show the version in the footer via a JS fetch.
docker-compose passes APP_VERSION through to the running container.

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

web/wwwroot/css/myai.css

@@ -607,6 +607,13 @@ img {
     flex-wrap: wrap
 }
 
+.app-version {
+    font-size: .7rem;
+    color: var(--muted);
+    opacity: .5;
+    font-family: monospace
+}
+
 .cookie-overlay {
     position: fixed;
     left: 0;

web/wwwroot/cv-matcher/index.html

@@ -186,6 +186,7 @@
                     <a data-legal="privacy" href="/legal/privacy-en.html" target="_blank" data-i18n="legal.privacy">Privacy</a>
                     <a data-legal="cookies" href="/legal/cookies-en.html" target="_blank" data-i18n="legal.cookies">Cookies</a>
                 </div>
+                <span id="app-version" class="app-version"></span>
                 <a href="#top" class="back-to-top btn btn-dark btn-sm shadow" data-i18n="footer.top">Back to top</a>
             </div>
         </footer>

web/wwwroot/index.html

@@ -189,6 +189,7 @@
                     <a data-legal="privacy" href="/legal/privacy-en.html" target="_blank" data-i18n="legal.privacy">Privacy</a>
                     <a data-legal="cookies" href="/legal/cookies-en.html" target="_blank" data-i18n="legal.cookies">Cookies</a>
                 </div>
+                <span id="app-version" class="app-version"></span>
                 <a href="#top" class="back-to-top btn btn-dark btn-sm shadow" data-i18n="footer.top">Back to top</a>
             </div>
         </footer>

web/wwwroot/js/main.js

@@ -262,6 +262,13 @@
 	}
 
 	$('#year').text(new Date().getFullYear());
+
+	$.getJSON('/version').done(function (data) {
+		if (data && data.version) {
+			$('#app-version').text('v' + data.version);
+		}
+	});
+
 	applyLanguage(currentLang());
 	$('.lang-flag').on('click', function () {
 		applyLanguage($(this).data('lang'));