core: implement protocol governance panel

[EmeditWeb]

Problem

No interface exists for protocol admin management.
Admin operations require raw API calls.

What To Build

Build /admin page with:

1. Protocol parameters panel
2. Vendor approval queue
3. Loan review queue
4. Protocol stats overview
5. Audit log viewer

Files To Touch

• src/pages/Admin.tsx (new)
• src/hooks/useAdmin.ts (new)
• src/router/index.tsx

Acceptance Criteria

• Non-admin wallets cannot access /admin
• Parameter updates build correct XDR
• Vendor approval triggers API call
• Audit log loads and paginates
• npm run build passes

Mandatory Checks Before PR

• npm run build passes
• No any types
• PR references this issue

[Godfrey-Delight]

Hi maintainer, I would love to work on this issue