Add search and filter controls to the admin member list

[Lakes41]

Difficulty: Intermediate
Type: feature

Background
The admin dashboard's member list surface (backed by GET /v1/members, which returns all member rows per the README's Live API endpoints table) is one of the MVP admin features.

Problem
Since GET /v1/members returns the full list with no server-side filtering, the admin UI currently has no client-side way to search by wallet/name or filter by role/tier, making the list unwieldy for communities with many members.

Expected outcome
The admin member list page includes a search input (matches wallet address/name) and filter dropdowns (role, tier), all applied client-side against the fetched /v1/members data, with results updating instantly as filters change.

Suggested implementation

• Add a client component wrapping the member list with local filter state (search text, role, tier).
• Add a debounced search input and filter dropdowns above the table.
• Ensure the mock API (lib/api/mock.ts) seed data includes enough variety (multiple roles/tiers) to meaningfully exercise the filters in mock mode.
• Add an empty-state message when filters return no matches.

Acceptance criteria

• Search matches partial wallet address or name
• Role and tier filters combine correctly with search
• Works correctly in both mock mode and against a live guildpass-core backend
• Empty state displayed when no members match

Likely affected files/directories

• app/admin/ (member list page)
• lib/api/mock.ts
• components/

[NkechiOgbuji]

Please assign to me. Thank you

[grantfox-oss]

🦊 GrantFox — @NkechiOgbuji has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #323)
2. Your PR will be reviewed by the Adamantine-guild maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@NkechiOgbuji's PR #366 was approved and merged by @Lakes41.

🏆 @NkechiOgbuji: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (436 total points). Track your full progress on GrantFox.

👏 Great work, @NkechiOgbuji! Keep contributing to Adamantine-guild.