feat(i18n): update language support to 77 languages

- Remove Russian (ru) per requirement
- Keep Esperanto (eo) per user feedback
- Add 29 new languages: am, az, bn, gu, ha, hi, hy, id, ig, jv, ka,
  kk, km, ml, mn, mr, ms, ne, si, sw, ta, te, th, tl, ur, uz, yo,
  zh-TW, zu
- Create 29 new translation JSON files seeded from en.json
- Remove frontend/translations/ru.json
- Update SUPPORTED_LANGUAGES list and docstring (49 → 77)
- Update tests: count 49→77, code set updated
- Update docs/InternationalizationGuide.md: count and table

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/test_i18n.py

@@ -326,7 +326,7 @@ class TestSupportedLanguages:
 
     @pytest.mark.unit
     def test_ten_languages_supported(self) -> None:
-        assert len(SUPPORTED_LANGUAGES) == 49
+        assert len(SUPPORTED_LANGUAGES) == 77
 
     @pytest.mark.unit
     def test_supported_codes_set(self) -> None:
@@ -368,17 +368,45 @@ class TestSupportedLanguages:
             "sr",
             "tr",
             "uk",
-            "ru",
             "he",
             "ar",
             "fa",
             "af",
             "zh",
+            "zh-TW",
             "ja",
             "ko",
             "vi",
             "pa",
             "kn",
+            "hi",
+            "bn",
+            "gu",
+            "ml",
+            "mr",
+            "ta",
+            "te",
+            "ur",
+            "si",
+            "ne",
+            "th",
+            "km",
+            "id",
+            "ms",
+            "jv",
+            "tl",
+            "mn",
+            "kk",
+            "uz",
+            "az",
+            "hy",
+            "ka",
+            "sw",
+            "am",
+            "ha",
+            "yo",
+            "ig",
+            "zu",
             "eo",
         }
         assert SUPPORTED_LANGUAGE_CODES == expected
@@ -403,7 +431,7 @@ class TestI18nAPI:
         assert response.status_code == 200
         data = response.json()
         assert "languages" in data
-        assert len(data["languages"]) == 49
+        assert len(data["languages"]) == 77
         assert data["default"] == "en"
         # Verify each language has required fields
         for lang in data["languages"]: