Vitest 4.1.2 release notes

This release bumps Vitest's flatted version and removes version pinning to resolve flatted's CVE related issues (https://github.com/vitest-dev/vitest/issues/9975).

Don't resolve setupFiles from parent directory - by @hi-ogawa in https://github.com/vitest-dev/vitest/issues/9960 (7aa93)
Ensure sequential mock/unmock resolution - by @hi-ogawa and Claude Opus 4.6 in https://github.com/vitest-dev/vitest/issues/9830 (7c065)
browser: Take failure screenshot if toMatchScreenshot can't capture a stable screenshot - by @macarie in https://github.com/vitest-dev/vitest/issues/9847 (faace)
coverage: Correct coverageConfigDefaults values and types - by @Arthie in https://github.com/vitest-dev/vitest/issues/9940 (b3c99)
pretty-format: Fix output limit over counting - by @hi-ogawa in https://github.com/vitest-dev/vitest/issues/9965 (d3b7a)
Disable colors if agent is detected - by @sheremet-va and @AriPerkkio in https://github.com/vitest-dev/vitest/issues/9851 (6f97b)