feat(web): show build info and theme menu [CI]

web/vite.config.ts

@@ -1,9 +1,30 @@
+import { execFileSync } from 'node:child_process';
+import { readFileSync } from 'node:fs';
 import { fileURLToPath } from 'node:url';
 import react from '@vitejs/plugin-react';
 import { defineConfig } from 'vitest/config';
 
+const webRoot = fileURLToPath(new URL('.', import.meta.url));
+const webPackage = JSON.parse(readFileSync(new URL('./package.json', import.meta.url), 'utf8')) as { version: string };
+
+function gitValue(...args: string[]): string {
+  try {
+    return execFileSync('git', args, { cwd: webRoot, encoding: 'utf8', stdio: ['ignore', 'pipe', 'ignore'] }).trim() || 'unknown';
+  } catch {
+    return 'unknown';
+  }
+}
+
+const buildInfo = {
+  frontendVersion: webPackage.version,
+  commit: process.env.WEBDROP_BUILD_COMMIT ?? gitValue('rev-parse', '--short=12', 'HEAD'),
+  tag: process.env.WEBDROP_BUILD_TAG ?? gitValue('describe', '--tags', '--exact-match', 'HEAD'),
+  builtAt: process.env.WEBDROP_BUILD_TIME ?? new Date().toISOString(),
+};
+
 export default defineConfig({
   plugins: [react()],
+  define: { __WEBDROP_BUILD_INFO__: JSON.stringify(buildInfo) },
   resolve: {
     alias: {
       '@': fileURLToPath(new URL('./src', import.meta.url)),