feat(i18n): author es/fr/ja annotation translations + merge into manifest

41 clips, 753 string-variants per language, structure-validated (key-sets
and tier-counts identical to en). Escalation semantics preserved.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_i18n_manifest.py

@@ -0,0 +1,25 @@
+import json
+from pathlib import Path
+
+LANGS = ["en", "es", "fr", "ja"]
+MANIFEST = Path("simulator/sample_media/manifest.json")
+
+
+def _tier_len(v):
+    return len(v) if isinstance(v, list) else 0  # 0 = plain string
+
+
+def test_every_clip_has_all_languages_with_matching_shape():
+    manifest = json.loads(MANIFEST.read_text(encoding="utf-8"))
+    for clip in manifest["clips"]:
+        s = clip.get("strings", {})
+        en = s.get("en")
+        if not en:
+            continue
+        for lang in LANGS:
+            assert lang in s, f"{clip['id']} missing language {lang}"
+            assert set(s[lang]) == set(en), f"{clip['id']}/{lang} key-set differs from en"
+            for key, en_val in en.items():
+                assert _tier_len(s[lang][key]) == _tier_len(en_val), (
+                    f"{clip['id']}/{lang}/{key} tier-count differs from en"
+                )