Resolve marketplace-search and dashboard accessibility findings (keyboard, labels, live regions)

[1nonlypiece]

📌 Description

The accessibility audit produced concrete findings for the marketplace
(design/accessibility-audit/findings/03-marketplace.md) and dashboard
(04-dashboard.md), with a remediation-plan.md and acceptance-criteria.md.
The marketplace search/typeahead (MarketplaceHeader.tsx,
MarketplaceFilters.tsx) and dashboard charts need keyboard operability,
correct labelling, and live-region announcements.

This issue remediates the marketplace and dashboard accessibility findings.

Goal: marketplace search and dashboard surfaces meet the audit's
acceptance criteria for keyboard, labelling, and announcements.

🎯 Requirements and Context

• Make the search/typeahead in MarketplaceHeader.tsx fully keyboard operable
  (arrow navigation, Enter to select, Esc to dismiss) with aria-activedescendant
  and a labelled combobox.
• Announce result counts / empty results via a polite live region.
• Ensure filter controls in MarketplaceFilters.tsx have accessible names and
  states.
• Give dashboard charts (HealthMetrics*Chart.tsx) text alternatives /
  summaries per 04-dashboard.md.
• Satisfy the items in design/accessibility-audit/acceptance-criteria.md.

🛠️ Suggested Execution

1. Create a branch

git checkout -b feature/a11y-marketplace-dashboard

2. Implement changes

• Update MarketplaceHeader.tsx, MarketplaceFilters.tsx, and the dashboard
  chart components per the findings.
• Add tests asserting roles, labels, keyboard interactions, and live regions.

3. Test and commit

• Run npm test.
• Edge cases: empty results announcement, keyboard-only navigation, no-mouse
  filter toggle, chart with no data.

Example commit message

fix: remediate marketplace and dashboard accessibility findings

✅ Guidelines

• Minimum 95% test coverage on changed interaction logic.
• Clear documentation mapping changes to audit findings.
• Timeframe: 96 hours.

🏷️ Labels

type-security · type-enhancement · area-frontend · MAYBE REWARDED · GRANTFOX OSS · OFFICIAL CAMPAIGN

💬 Community & Support

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