feat(ui): add git version info display in header

- Display current branch/tag and commit hash in navbar center
- Show dirty working directory indicator with yellow badge
- Add automatic build info generation in Task workflow
- Include build timestamp and user information
- Style with responsive design (hidden on mobile)
- Add .gitignore entries for generated build artifacts

static/css/version-info.css

@@ -0,0 +1,36 @@
+/* Navbar version info styles */
+.navbar-version-info {
+  flex: 1;
+  justify-content: center;
+  font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
+}
+
+.navbar-version-info code {
+  background: rgba(255, 255, 255, 0.1);
+  padding: 0.1rem 0.3rem;
+  border-radius: 0.2rem;
+  font-size: 0.8rem;
+}
+
+.navbar-version-info .badge {
+  font-size: 0.6rem;
+  padding: 0.1rem 0.3rem;
+}
+
+/* Hide on small screens */
+@media (max-width: 767px) {
+  .navbar-version-info {
+    display: none !important;
+  }
+}
+
+/* Additional responsive tweaks */
+@media (min-width: 768px) and (max-width: 991px) {
+  .navbar-version-info {
+    flex: 0.5;
+  }
+  
+  .navbar-version-info small {
+    font-size: 0.75rem;
+  }
+}