fix: allow access key expiration beyond current year

[GatewayJ]

Pull Request

Description

Fix the shared date-time picker so access key expiration dates can navigate beyond the end of the current year. react-day-picker implicitly limits captionLayout="dropdown" to the current year when no explicit end month is provided; using the month-only dropdown preserves month selection without introducing an arbitrary future limit.

Add a regression test that renders the real DayPicker configuration at December 2026 and verifies that navigation to the next month remains enabled. The PR also retains the Next.js-generated AGENTS.md guidance refresh required by the repository.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code refactoring
• Performance improvement
• Test improvements
• Security fix

Testing

• Unit tests added/updated
• Manual testing completed

pnpm install --frozen-lockfile --registry=https://registry.npmmirror.com
pnpm test:run
pnpm type-check
pnpm lint
pnpm prettier --check components/datetime-picker.tsx tests/lib/datetime-picker.test.js
git diff --check

Manually verified navigation from August 2026 through January 2027, date selection in 2027, keyboard-accessible controls, and layout at desktop and 375px mobile widths with no console warnings or horizontal overflow.

Checklist

• Code follows the project's style guidelines
• Self-review completed
• TypeScript types are properly defined
• All commit messages are in English (Conventional Commits)
• All existing tests pass
• No new dependencies added, or they are justified

Related Issues

N/A

Screenshots (if applicable)

N/A — this changes calendar navigation behavior without changing visual styling.

Additional Notes

The full-repository Prettier check still reports the pre-existing, unchanged components/object/tiff-viewer.tsx on origin/main; both files changed by this fix pass Prettier.