fix(i18n): stop repairCatalog crashing on un-bootstrapped locale keys (#11728)

en.json carries ~190 keys per locale that the locale catalogs have not been
bootstrapped with yet, so every repair-locale-catalog run threw a TypeError
before doing any work. Skip missing leaves instead.

Split out of #11728 so the crash fix can land without the catalog
regeneration, which still needs native-speaker review.

Co-authored-by: Turtle-Hwan <turtlehwan@gmail.com>

Co-authored-by: Orca <help@stably.ai>

config/scripts/locale-repair-catalog-missing-leaves.test.mjs

@@ -0,0 +1,30 @@
+import { describe, expect, it } from 'vitest'
+
+import { repairCatalog } from './locale-translation-policy.mjs'
+
+// Regression: en.json routinely carries keys a locale catalog has not been bootstrapped with yet
+// (~190 per locale at the time of writing), which crashed the whole repair run before it did any work.
+describe('repairCatalog with un-bootstrapped keys', () => {
+  const enCatalog = {
+    auto: {
+      lib: { agent: { catalog: { '760bc6883d': 'Codex' } } },
+      components: { untranslated: 'Continue', nested: { alsoMissing: 'Refresh' } }
+    }
+  }
+
+  const translatedOnly = () => ({ auto: { lib: { agent: { catalog: { '760bc6883d': '사본' } } } } })
+
+  it('skips leaves the locale catalog is missing instead of throwing', () => {
+    for (const locale of ['ko', 'ja', 'zh', 'es']) {
+      const localeCatalog = translatedOnly()
+      expect(() => repairCatalog(enCatalog, localeCatalog, locale), locale).not.toThrow()
+      expect(localeCatalog.auto.components, locale).toBeUndefined()
+    }
+  })
+
+  it('still repairs the leaves that are present', () => {
+    const localeCatalog = translatedOnly()
+    expect(repairCatalog(enCatalog, localeCatalog, 'ko')).toBe(1)
+    expect(localeCatalog.auto.lib.agent.catalog['760bc6883d']).toBe('Codex')
+  })
+})

config/scripts/locale-translation-policy.mjs

@@ -551,6 +551,11 @@ export function repairCatalog(enCatalog, localeCatalog, locale) {
 
   for (const leaf of leaves) {
     const current = leaf.key.split('.').reduce((cursor, part) => cursor?.[part], localeCatalog)
+    // Why: en.json carries keys the locale catalog has not been bootstrapped with yet; repair only
+    // rewrites values that already exist, so skip instead of crashing on undefined.
+    if (typeof current !== 'string') {
+      continue
+    }
     const next = repairTranslatedValue({
       key: leaf.key,
       enValue: leaf.value,