Force dynamic content to English + rename app to Akiora

[kiro-agent]

This pull request was created by @kiro-agent on behalf of @Deadendev 👻

Comment with /kiro fix to address specific feedback or /kiro all to address everything.
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Summary

Two requested changes:

1. Force dynamic content (anime titles, summaries) to English — even though the Bangumi API only returns Chinese/Japanese, the app now machine-translates it on device.
2. Rename the app to "Akiora" across the UI and native platforms.

1. Force English

Bangumi provides only name (original, usually Japanese) and name_cn (Chinese) — there is no English field. So the app now translates at display time:

• TranslationService (lib/services/translation/translation_service.dart): translates non-Latin text to English using a keyless translation endpoint, with an in-memory + Hive-persistent cache (each unique string translated once), request de-duplication, a dedicated proxy-aware Dio client, and graceful fallback to the original text on any failure.
• TranslatedText widget (lib/bean/widget/translated_text.dart): a drop-in Text replacement that shows the original immediately, then swaps in the cached English translation. The underlying data model is never mutated.
• Wired into: popular/recommended, search results, and tracking grids (BangumiContent), the info page title, watch-history cards, timeline cards, and the info-page summary.
• New "Force English" toggle in Interface settings (default on, key forceEnglishTranslation).

Why display-time translation: name_cn is also used as the plugin search keyword and as storage identifiers/folder names. Translating the data would break plugin search and downloads, so only the displayed text is translated.

2. Rename to Akiora

Changed user-visible names to Akiora:

• Dart: window/app title, main app bar, exit dialog, tray tooltip + menu item, X11 + desktop-shortcut prompts, audio notification channel name, plugin version-compatibility message.
• Native: Android android:label, iOS CFBundleDisplayName, macOS CFBundleDisplayName, Windows window title (+ FindWindow single-instance match kept consistent) and Runner.rc ProductName/FileDescription, Linux .desktop Name=, web <title>/manifest.

Intentionally kept unchanged (renaming would break things):

• Dart package name kazumi and all package:kazumi/... imports; KazumiLogger/KazumiDialog/KazumiCaptcha identifiers.
• Auto-updater asset prefix Kazumi-$version (must match the upstream GitHub release asset names).
• Linux tray icon id io.github.Predidit.Kazumi, bundle/application ids, executable/binary names.
• "About" external links (homepage, repo, Telegram group) still point to the upstream Kazumi project.

Testing / Limitations

• Flutter SDK is not available in this environment, so flutter analyze/build was not run — please run them before merging.
• Translation requires network access to the translation endpoint; it respects the app's proxy setting and fails gracefully (shows original text) when unreachable. Quality is machine-translation level.
• Not yet translated (can be extended): genre tags, character/staff names, user comments, and the in-player title string. Titles + summaries (the main ask) are covered.
• macOS shows "Akiora" via CFBundleDisplayName while keeping PRODUCT_NAME (bundle/output name) stable.