chore(web): clean up low-risk lint warnings

[Uarmagan]

Summary

This PR cleans up the lowest-risk lint noise in mechanical passes. It removes unused imports, lets Biome reorder class names, adds explicit type="button" attributes to action buttons, and simplifies literal string-key property access where Biome can prove dot access is equivalent.

The intent is to reduce warning and info noise without touching the more judgment-heavy categories like React hook dependencies or non-null assertions.

What changed

• Removed unused web imports.
• Sorted class names where Biome requested it.
• Added explicit button types to action buttons and button fixtures in tests.
• Replaced simple literal-key access with dot access across backend, core, scripts, and web files.

Validation

• bunx biome check . --only=lint/correctness/noUnusedImports --only=lint/nursery/useSortedClasses --only=lint/a11y/useButtonType --max-diagnostics=none
  • Passed with no remaining warnings in those three categories.
• bunx biome check . --only=lint/complexity/useLiteralKeys --max-diagnostics=none
  • Passed with no remaining literal-key diagnostics.
• bun run lint
  • Exits successfully.
  • Warnings dropped from 850 to 694.
  • Info items dropped from 182 to 31.
• bun run test:core
  • 134 passed, 0 failed.
• bun run test:scripts
  • 57 passed, 0 failed.
• bun run test:backend
  • 459 passed, 1 skipped, 0 failed.
• bun test --cwd packages/web src/common/hooks/useBufferedVisibility.test.ts src/common/hooks/useEventDNDActions.test.ts src/components/DND/DNDContext.test.tsx src/components/Tooltip/TooltipWrapper.test.tsx src/ducks/events/sagas/someday.sagas.test.ts src/views/Day/components/ShortcutsSidebar/ShortcutsSidebar.test.tsx
  • 33 passed, 0 failed.
• bun test --cwd packages/web src/auth/compass/session/session.util.test.ts src/common/parsers/view.parser.test.ts
  • 21 passed, 0 failed.

Note: I also tried the full bun run test:web suite before the literal-key follow-up. It progressed through many passing files, then Bun itself crashed while starting src/common/utils/app-init.util.test.ts. The focused touched-file test runs above completed successfully.