chore: resolve all 86 ESLint findings

[revikornmann]

Summary

• Drives the project from 86 ESLint problems (50 errors, 36 warnings) to 0/0
• Mostly real fixes; targeted eslint-disable only where the rule misfires on legitimate native or wrapper patterns

What changed

• A11y (11 errors) — real semantic improvements:
  • DatePicker: each day button wrapped in <div role="gridcell"> with aria-selected on the gridcell
  • DocumentCanvas: arrow-key panning when zoomed, plus role="application", aria-label, conditional tabIndex
  • SmsOtpField: removed aria-invalid from role="group" (not supported there) and applied to each digit input; also removed a stray no-op arrow expression in onFocus
  • Tabs: tabIndex={-1} on the tablist
  • DatePicker.stories: replaced unattached <label> with <div> + aria-label on DatePicker
  • Targeted disables only for native <dialog> backdrop-click in Dialog/Drawer, and Input/Select wrapper divs that forward clicks to real inputs (which themselves provide full keyboard support)
• Storybook hooks (13 errors) — converted render: (args) => { …useState… } arrows to render: function PascalNameRender(args) {…} in Dialog, FileUpload, SegmentGroup, and View stories so react-hooks/rules-of-hooks recognizes them as components
• Scripts (~14 errors) — Object.hasOwn instead of obj.hasOwnProperty, optional catch bindings, removed unused requires and a dead origLog capture
• 36 warnings — removed unused imports/locals across components and tests; replaced any types with Record<string, unknown>, structural types, or inferred Storybook arg types where straightforward; Toast.stories simplified position={undefined as any} to position={undefined} since the prop is already optional

Test plan

• npm run lint — 0 errors, 0 warnings
• npm run test:unit — 438/438 passing
• npx tsc --noEmit — no new errors (existing .figma.tsx errors are unrelated)
• npm run test:visual — pre-existing infrastructure issue on main (getByTestId('spec') strict-mode violations); not caused by this branch
• Manual: spot-check DatePicker in Storybook to confirm the gridcell wrapping didn't disrupt the 7-column grid layout