- Downgrade eslint 10.0.0 → 9.x (incompatible with eslint-config-next)
- Update 30+ test file imports from .js to .ts (accountSelector, combo, etc.)
- Add open-sse/** to ESLint ignores (no TS parser configured for it)
- All CI steps now pass: lint ✅, build ✅, unit tests (368/0) ✅