feat(usage): improve custom template system with variable hints and validation fixes (#628)

* feat(usage): improve custom template with variables display and explicit type detection

Combine two feature improvements:
1. Display supported variables ({{baseUrl}}, {{apiKey}}) with actual values in custom template mode
2. Add explicit templateType field for accurate template mode detection

## Changes

### Frontend
- Display template variables with actual values extracted from provider settings
- Add templateType field to UsageScript for explicit mode detection
- Support template mode persistence across sessions

### Backend
- Add template_type field to UsageScript struct
- Improve validation logic based on explicit template type
- Maintain backward compatibility with type inference

### I18n
- Add "Supported Variables" section translation (zh/en/ja)

### Benefits
- More accurate template mode detection (no more guessing)
- Better user experience with variable hints
- Clearer validation rules per template type

* fix(usage): resolve custom template cache and validation issues

Combine three bug fixes to make custom template mode work correctly:

1. **Update cache after test**: Testing usage script successfully now updates the main list cache immediately
2. **Fix same-origin check**: Custom template mode can now access different domains (SSRF protection still active)
3. **Fix field naming**: Unified to use autoQueryInterval consistently between frontend and backend

## Problems Solved

- Main provider list showing "Query failed" after successful test
- Custom templates blocked by overly strict same-origin validation
- Auto-query intervals not saved correctly due to inconsistent naming

## Changes

### Frontend (UsageScriptModal)
- Import useQueryClient and update cache after successful test
- Invalidate usage cache when saving script configuration
- Use standardized autoQueryInterval field name

### Backend (usage_script.rs)
- Allow custom template mode to bypass same-origin checks
- Maintain SSRF protection for all modes

### Hooks (useProviderActions)
- Invalidate usage query cache when saving script

## Impact

Users can now use custom templates freely while security validations remain intact for general templates.

* fix(usage): correct provider credential field names

- Claude: support both ANTHROPIC_API_KEY and ANTHROPIC_AUTH_TOKEN
- Gemini: use GEMINI_API_KEY instead of GOOGLE_GEMINI_API_KEY
- Codex: use OPENAI_API_KEY and parse base_url from TOML config string

Addresses review feedback from PR #628

* style: format code

---------

Co-authored-by: Jason <farion1231@gmail.com>

src-tauri/src/deeplink/provider.rs

@@ -225,6 +225,7 @@ fn build_provider_meta(request: &DeepLinkImportRequest) -> Result<Option<Provide
         }),
         access_token: request.usage_access_token.clone(),
         user_id: request.usage_user_id.clone(),
+        template_type: None, // Deeplink providers don't specify template type (will use backward compatibility logic)
         auto_query_interval: request.usage_auto_interval,
     };