feat: Spec product version, build bake, Admin UI label.

Resolve VERSION from EventHubSpec; VITE_APP_BUILD from run_number; show Admin UI / API as version.build (sha).

Co-authored-by: Cursor <cursoragent@cursor.com>

vite.config.ts

@@ -7,6 +7,7 @@ const apiBaseUrl = process.env.VITE_API_BASE_URL ?? 'https://admin-api.dev.event
 const wsUrl = process.env.VITE_WS_URL ?? 'wss://admin-ws.dev.eventhub.local';
 
 const appVersion = process.env.VITE_APP_VERSION ?? '0.0';
+const appBuild = process.env.VITE_APP_BUILD ?? '0';
 const gitSha = process.env.VITE_GIT_SHA ?? 'dev';
 const builtAt = process.env.VITE_BUILT_AT ?? '';
 
@@ -14,6 +15,7 @@ export default defineConfig({
     plugins: [react(), tailwindcss()],
     define: {
         'import.meta.env.VITE_APP_VERSION': JSON.stringify(appVersion),
+        'import.meta.env.VITE_APP_BUILD': JSON.stringify(appBuild),
         'import.meta.env.VITE_GIT_SHA': JSON.stringify(gitSha),
         'import.meta.env.VITE_BUILT_AT': JSON.stringify(builtAt),
     },