feat(ci): add i18n key consistency check for frontend locales (#2133)

* feat(ci): add i18n key consistency check workflow

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Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* feat(ci): replace eval with line-by-line parser, add permissions block

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Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

.github/workflows/check-i18n.yml

@@ -0,0 +1,25 @@
+name: Check i18n Keys
+
+on:
+  push:
+    branches:
+      - main
+      - master
+
+jobs:
+  check-i18n:
+    name: Check i18n Key Consistency
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Check i18n keys against en-US reference
+        run: node web/scripts/check-i18n.mjs

web/scripts/check-i18n.mjs

@@ -0,0 +1,145 @@
+#!/usr/bin/env node
+/**
+ * Check that all i18n locale files have the same keys as en-US.ts (the reference).
+ * Reports missing keys (present in en-US but absent in the locale) and
+ * extra keys (present in the locale but absent in en-US).
+ * Exits with code 1 if any mismatch is found.
+ *
+ * Keys are extracted using a line-by-line parser that handles the known format
+ * of the locale files (no eval or dynamic code execution is used).
+ */
+
+import { readFileSync, readdirSync } from 'fs';
+import { resolve, dirname, join } from 'path';
+import { fileURLToPath } from 'url';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const LOCALES_DIR = resolve(__dirname, '../src/i18n/locales');
+const REFERENCE = 'en-US.ts';
+
+/**
+ * Extract all dot-notation leaf keys from a TypeScript locale file.
+ *
+ * The expected file format is:
+ *   const <varName> = {
+ *     key: 'value',
+ *     nested: {
+ *       subKey: 'value',
+ *     },
+ *   };
+ *   export default <varName>;
+ *
+ * The parser tracks indentation depth to build dot-separated key paths and
+ * never executes the file content.
+ */
+function extractKeys(filePath) {
+  let src = readFileSync(filePath, 'utf8');
+
+  // Remove UTF-8 BOM if present
+  if (src.charCodeAt(0) === 0xfeff) {
+    src = src.slice(1);
+  }
+
+  const lines = src.split('\n');
+  const keys = [];
+  // Stack of { key, indent } pairs representing the current nesting path
+  const stack = [];
+
+  // Matches an object key at the start of a line (identifier or quoted string)
+  // Captures: [indent, keyName, hasOpenBrace]
+  const KEY_RE = /^(\s+)([\w]+)\s*:/;
+  const OPEN_BRACE_RE = /\{\s*$/;
+  const CLOSE_BRACE_RE = /^\s*\},?\s*$/;
+
+  for (const line of lines) {
+    if (CLOSE_BRACE_RE.test(line)) {
+      // Pop the stack when we encounter a closing brace line
+      const lineIndent = line.match(/^(\s*)/)[1].length;
+      while (stack.length > 0 && stack[stack.length - 1].indent >= lineIndent) {
+        stack.pop();
+      }
+      continue;
+    }
+
+    const m = line.match(KEY_RE);
+    if (!m) continue;
+
+    const indent = m[1].length;
+    const keyName = m[2];
+
+    // Pop stack entries that are at the same or deeper indent level
+    while (stack.length > 0 && stack[stack.length - 1].indent >= indent) {
+      stack.pop();
+    }
+
+    const prefix = stack.map((e) => e.key).join('.');
+    const fullKey = prefix ? `${prefix}.${keyName}` : keyName;
+
+    if (OPEN_BRACE_RE.test(line)) {
+      // This is a parent (nested object) key — push onto stack, don't record as leaf
+      stack.push({ key: keyName, indent });
+    } else {
+      // This is a leaf key
+      keys.push(fullKey);
+    }
+  }
+
+  return keys;
+}
+
+function main() {
+  const files = readdirSync(LOCALES_DIR).filter((f) => f.endsWith('.ts'));
+
+  if (!files.includes(REFERENCE)) {
+    console.error(`Reference file ${REFERENCE} not found in ${LOCALES_DIR}`);
+    process.exit(1);
+  }
+
+  const refKeys = new Set(extractKeys(join(LOCALES_DIR, REFERENCE)));
+  let hasError = false;
+
+  for (const file of files) {
+    if (file === REFERENCE) continue;
+
+    const locale = file.replace('.ts', '');
+    let localeKeys;
+    try {
+      localeKeys = new Set(extractKeys(join(LOCALES_DIR, file)));
+    } catch (e) {
+      console.error(`[${locale}] Failed to parse file: ${e.message}`);
+      hasError = true;
+      continue;
+    }
+
+    const missing = [...refKeys].filter((k) => !localeKeys.has(k));
+    const extra = [...localeKeys].filter((k) => !refKeys.has(k));
+
+    if (missing.length === 0 && extra.length === 0) {
+      console.log(`[${locale}] ✅ All keys match.`);
+    } else {
+      hasError = true;
+      console.log(`\n[${locale}] ❌ Key mismatch detected:`);
+      if (missing.length > 0) {
+        console.log(`  Missing keys (in en-US but not in ${locale}):`);
+        for (const k of missing) {
+          console.log(`    - ${k}`);
+        }
+      }
+      if (extra.length > 0) {
+        console.log(`  Extra keys (in ${locale} but not in en-US):`);
+        for (const k of extra) {
+          console.log(`    + ${k}`);
+        }
+      }
+    }
+  }
+
+  if (hasError) {
+    console.log('\n❌ i18n key check failed. Please fix the mismatches above.');
+    process.exit(1);
+  } else {
+    console.log('\n✅ All i18n locale files have matching keys.');
+  }
+}
+
+main();