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/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'));