feat: implement Dashboard component with controlled/uncontrolled navi…

[extolkom]

Summary

Closes #569

package.json was missing main, module, exports, and files fields
needed for npm distribution, and vite.config.ts only had an app build
(index.html entry), not a library build mode.

Changes

• Added Vite library build mode targeting src/components/index.ts,
  outputting ESM and CJS bundles plus TypeScript declarations to dist/
• package.json: added main, module, types, exports map, and
  files: ["dist", "README.md", "CHANGELOG.md"]

Note on related issue #568

Issue #568 in this repo has near-identical scope. [FILL IN: state here whether
#568 was merged, still open, or unstarted at the time of this PR, and how this
PR relates to it — reviewer will want this context.]

Verification

• npm test — 83 test files / 1,352 tests passing
• npm run typecheck — 0 errors
• npm run test:exports — passing
• npm run build — dist/index.js, dist/index.cjs, dist/index.d.ts,
  dist/style.css all generated
• npm pack --dry-run tarball contents — not yet confirmed against the
  acceptance criteria (dist/, README.md, CHANGELOG.md only)
• Real consumer import smoke test (ESM + CJS) — not yet run

Note on diff scope

This branch's working history touched some files outside the immediate
package.json/vite-config scope during investigation
(SorokitProvider.tsx/Dashboard.tsx area). [FILL IN: confirm here whether the
final diff actually includes changes to those files, and if so, why they were
necessary for this fix — if they're not needed, please remove them from the
diff before merging.]