feat(review): add local ESLint quality findings

[LarryHu0217]

Summary

• run the project's existing local ESLint only for changed JavaScript and TypeScript files
• map ESLint JSON findings into the shared review finding contract and reuse the existing sidebar/send-to-agent flow
• degrade silently when no ESLint config applies, while surfacing actionable provider failures
• add an explicit Refresh findings control for the current diff

Validation

• npm run check
• npm test (116 files passed, 2 skipped; 1,861 tests passed, 23 skipped)
• Electron IPC finding tests and client review tests

Fixes #260