feat: Add full i18n support to Smart Mind Map plugin

- Consolidated smart_mind_map.py and smart_mind_map_cn.py into a single file.
- Added TRANSLATIONS dictionary supporting 17 languages (en-US, ko-KR, fr-FR, es-AR, en-CA, fr-CA, ja-JP, de-DE, zh-HK, it-IT, zh-CN, en-GB, es-MX, id-ID, es-ES, de-AT, en-AU, vi-VN).
- Implemented automatic language detection with fallback to browser/local storage.
- Added localized date formatting for various locales.
- Added fallback mapping for regional variants (e.g. zh-TW -> zh-HK, es-AR -> es-ES).
- Updated HTML/JS templates to use injected translations.
- Fixed SyntaxWarning in regex strings.
- Verified frontend rendering with Playwright.

Co-authored-by: Fu-Jie <33599649+Fu-Jie@users.noreply.github.com>

plugins/actions/smart-mind-map/smart_mind_map.py

@@ -1245,6 +1245,7 @@ class Action:
         }
         # Fallback mapping for variants not in TRANSLATIONS keys
         self.fallback_map = {
+            "zh-TW": "zh-HK",
             "es-AR": "es-ES",
             "es-MX": "es-ES",
             "fr-CA": "fr-FR",