fix(ui): add cursor pointer to buttons and link-buttons

[pmaxhogan]

Summary

Every interactive control in ui/src is a native <button> (this includes tab headers, icon buttons, and buttons styled to look like links) - Tailwind v3+ dropped the preflight cursor: pointer reset for buttons, so they were all falling back to the browser's default arrow cursor on hover.

Approach

Global rule, not per-component: one addition to ui/src/style.css's @layer base:

button:not(:disabled) {
  cursor: pointer;
}

:not(:disabled) keeps disabled buttons on the existing disabled:cursor-not-allowed Tailwind utility already present on the shared button-class constants (primaryButtonClasses / secondaryBtn / destructiveBtn etc. across AccountList.vue, SourceTable.vue, Restore.vue, About.vue, Activity.vue, SetupWizard.vue, ...) - both layers cascade correctly since Tailwind's utilities layer always wins over base regardless of source order/specificity.

No per-component changes were needed: a full sweep of ui/src found no @click handlers, role="button", or tabindex outside of native <button> elements, and the app's only other clickable-looking control (RouterLink, which renders <a href>) already gets a pointer cursor from the browser's default UA stylesheet. <select> and checkbox/toggle inputs were left alone - out of scope (native controls, not reported).

Verification

• pnpm -C ui lint - clean (only pre-existing i18n unused-key warnings, 0 errors)
• pnpm -C ui test:unit - 264/265 passing; router-first-run.test.ts's "lands a fresh install on the setup wizard" case timed out under full-suite load but passes cleanly in isolation (pre-existing flake, unrelated to a CSS-only change)
• pnpm -C ui build (vue-tsc --noEmit && vite build) - clean; confirmed compiled CSS contains button:not(:disabled){cursor:pointer}
• Ran the real dev server and drove it via claude-in-chrome, checking getComputedStyle(...).cursor on every <button> across Activity, About, Restore, and Setup Wizard: every enabled button reports pointer, every disabled button keeps its prior cursor (not-allowed via the existing utility, or the browser's disabled default where no utility applies) - zero regressions, zero visual changes beyond the cursor.

Refs #34

---

Co-Authored-By: Claude Fable 5 noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_01QZQVP2tUuTLh8oL31D8heC

[github-actions]

Coverage

Area	main	this PR	delta
Rust (lib crates)	78.70%	78.70%	+0.00 (OK)
UI (vue/ts)	88.58%	88.58%	+0.00 (OK)

Gate: passed - no coverage regression (epsilon 0.1 pp).