feat(antigravity): enable token counting via API with resilient routing

Introduces the capability to count tokens for Antigravity-backed requests. This implementation leverages the `countTokens` endpoint of the Antigravity API, replacing the prior unsupported stub.

Key aspects of this update include:

- **API Integration**: Direct integration with the Antigravity `countTokens` API, including necessary request payload translation and authentication.
- **Resilient Infrastructure**: A fallback mechanism has been established, allowing the system to attempt connections across multiple Antigravity base URLs to ensure request success even in the event of temporary service interruptions.
- **Model Aliasing**: Added mappings for `gemini-3-flash` and `gemini-3-flash-preview` to ensure compatibility with the latest model variants.
- **Robust Error Handling**: Comprehensive error handling and logging are in place to manage failures during API interactions.

feat(antigravity): add Gemini 3 Flash Preview model definition with e…

…nhanced capabilities

refactor(antigravity): optimize response handling in Claude model wit…

…h JSON manipulation

Merge pull request #572 from router-for-me/watcher

refactor(watcher): extract auth synthesizer to synthesizer package

Fixed: #551

fix(translator): standardize content node handling across translators for assistant and tool calls

fix(translator): correct funcName extraction and ensure proper handli…

…ng of function response data in Antigravity Claude requests

Merge pull request #569 from router-for-me/watcher

Watcher Module Progressive Refactoring - Phase 1

feat(remote-management): add support for custom GitHub repository for…

… panel updates

Introduce `panel-github-repository` in the configuration to allow specifying a custom repository for management panel assets. Update dependency versions and enhance asset URL resolution logic to support overrides.

docs: remove Amp CLI integration guides and update references

fix(translator): handle empty item type and string content in OpenAI …

…response parser