feat: add support ticket dashboard for bounty #4

[shuibui]

Summary

Adds a production-style Support Ticket Dashboard as a new page for MergeFund bounty #4.

MergeFund bounty ID: d1b53632-1a28-4690-b22e-486dc8cdac2b
Issue: #4

What changed:

• Added /support-tickets as a responsive Tailwind page with mock support queue data.
• Added filters for status and priority plus sorting by risk, priority, account value, and recency.
• Added SLA risk, average reply, key-account, workload, channel mix, and selected-ticket detail panels.
• Linked the page from the home page and top navigation.
• Fixed the existing create-bounty form validation state so the repository builds cleanly.
• Added committed desktop and mobile screenshots under screenshot/.

Screenshots / Demo

Desktop:

Mobile:

Video/GIF: not attached; full-page desktop and mobile screenshots are included.

Validation

• npm run lint
• npm run build

Note: lint reports the existing leaderboard <img> warning, unchanged by this PR. The build passes and generates /support-tickets as a static route.

Checklist

• Responsive on mobile
• No console errors expected from this page
• Matches acceptance criteria

Refs #4