fix: internationalize hardcoded strings in Jina embedder

[roomote]

This PR fixes hardcoded strings found during translation review of the Jina embedder implementation in PR #6416.

Issues Fixed

Hardcoded Strings in Jina Embedder

• Line 107: "Base64/binary embeddings are not supported" → t("embeddings:unsupportedEmbeddingFormat")
• Line 265: "Unknown error" → t("embeddings:unknownError")

Changes Made

1. Fixed Hardcoded Strings

• Replaced hardcoded error messages with proper i18n function calls
• Used existing unknownError translation key where available
• Added new unsupportedEmbeddingFormat translation key

2. Added Missing Translations

• Added unsupportedEmbeddingFormat translation to all 17 supported languages:
  • English, German, Spanish, French, Chinese (Simplified & Traditional)
  • Japanese, Italian, Portuguese (Brazil), Russian, Korean, Dutch
  • Polish, Turkish, Vietnamese, Hindi, Indonesian, Catalan
• Added missing jinaConfigMissing translation to backend embeddings.json files

Translation Coverage

• ✅ All UI text now uses i18n functions
• ✅ New translation key added to all supported languages
• ✅ No hardcoded user-facing strings remain

Related

• Addresses translation issues found in PR feat: add Jina as embedding provider for code indexing #6416 (Jina embedding provider)
• Complements PR fix: add missing Jina translations for PR #6416 #6417 (missing Jina translations)

Testing

• ✅ All linting checks pass
• ✅ All type checks pass
• ✅ Translation script validation pending (requires remaining translations to be added)

Remaining Work

The translation check script still reports missing translations for:

• Frontend Jina UI strings (jinaProvider, jinaApiKeyLabel, etc.) - these should be added in a separate PR focused on frontend translations
• Some backend jinaConfigMissing keys in languages not yet updated

This PR focuses specifically on fixing the hardcoded strings found in the Jina embedder implementation.

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Important

Internationalized hardcoded strings in Jina embedder and added support for Jina as an embedder provider with translations and configuration updates.

• Internationalization:
  • Replaced hardcoded strings in Jina embedder with i18n function calls in jina.ts.
  • Added unsupportedEmbeddingFormat and unknownError translation keys.
  • Added translations for unsupportedEmbeddingFormat in 17 languages.
• Jina Embedder Support:
  • Added Jina as an embedder provider in codebase-index.ts, config-manager.ts, and service-factory.ts.
  • Implemented JinaEmbedder class in jina.ts for embedding operations.
  • Updated webviewMessageHandler.ts to handle Jina API key storage.
• UI and Configuration:
  • Updated CodeIndexPopover.tsx to include Jina provider options.
  • Added Jina API key validation and configuration in global-settings.ts.
  • Updated i18n files for UI text related to Jina configuration.

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[roomote]

Code Review Summary

This PR successfully internationalizes hardcoded strings in the Jina embedder and adds comprehensive Jina provider support. The implementation follows established patterns and maintains consistency with other embedding providers.

Critical Issues (Must Fix)

1. Missing jinaConfigMissing translation in Catalan

• File: src/i18n/locales/ca/embeddings.json
• The Catalan translation file is missing the jinaConfigMissing key that was added to German and English files
• This will cause runtime errors when using Catalan locale with Jina provider

2. Incomplete Jina API key handling in UI secret status

• File: webview-ui/src/components/chat/CodeIndexPopover.tsx (lines 288-335)
• The secret status handler doesn't update codebaseIndexJinaApiKey field when receiving secret status updates
• Other providers (OpenAI, Gemini, Mistral) properly handle their API key placeholders, but Jina is missing

Important Suggestions (Should Consider)

3. Inconsistent translation key placement

• The new unsupportedEmbeddingFormat key appears at different line positions across language files
• Consider maintaining consistent ordering for better maintainability

4. Enhanced error handling specificity

• File: src/services/code-index/embedders/jina.ts (lines 264-268)
• Could provide more specific error messages for different HTTP status codes beyond 401 and 429

Minor Improvements (Nice to Have)

5. Documentation consistency

• Consider adding JSDoc comments to JinaEmbedder class methods for consistency with other embedder implementations

6. Translation validation

• Verify all 17 supported languages have consistent translation keys and proper formatting

Positive Aspects

✅ Proper internationalization implementation using t() function calls
✅ Consistent integration with existing embedding provider patterns
✅ Comprehensive UI integration with validation and error handling
✅ Well-structured JinaEmbedder class with proper batching and rate limiting
✅ Appropriate model profiles and default configurations
✅ Clean type definitions and schema updates

The core functionality is solid and follows established patterns well. The critical issues should be addressed before merging to ensure proper functionality across all supported locales.