Deduplicate identity search by best matching certificate

[BraydenLangley]

Summary

• Return one result per identity key by default from both IdentitySearchField and useIdentitySearch.
• Keep distinct keys even when their display names match. For duplicate certificates on one key, prefer the presentation whose name and certificate field type best match the query; keep the first on ties.
• Preserve the existing deduplicate={false} component option and add the same option to the headless hook.
• Bump to 2.0.1 because a merge to master runs the npm publication workflow.

Validation

• npm run lint:ci
• npm run typecheck
• npm run build
• npm run test:coverage (37 tests)
• npm run test:consumer (packed React 18/MUI 5 consumer)
• npm audit --audit-level=high
• Linked this worktree into the metanet-client-desktop branch and passed its 273 tests, lint, typecheck, and production build.

The desktop Send & Receive picker has a separate search implementation; its matching fix is in the companion desktop branch.

[codecov]

Codecov Report

❌ Patch coverage is 93.93939% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/utils/dedupeIdentities.ts	92.00%	0 Missing and 2 partials ⚠️

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