test: fix broken unit tests, add missing fixtures, and stabilize CI pipeline
- Fix os module mock pattern for Vitest v4 in proxy-ide-config tests
- Fix enterprise oauth_client_key expectations in cloudHandler-sync and token-manager-parity tests
- Fix proxy-controller integration test argument expectations
- Add missing proxy-parity JSON fixtures (OpenAI tools, Anthropic tool-use, Gemini SSE)
- Add reasoning_content mapping to convertClaudeToOpenAIResponse
- Fix google-api service test env var cache leak with resetModules + dynamic imports
- Fix proxy-metrics timer tests by calling onModuleInit in beforeEach
- Fix locale-sensitive number formatting in StatCard tests
- Add missing test files to version control (components, hooks, ipc, mocks, server, utils)
- Fix CI workflows: testing.yaml (use vitest run, add type-check job, npm cache), lint.yaml and format.yaml (add npm cache, concurrency, fix job names)