[Web] Username resolver page — look up any @username and display linked addresses

[ryzen-xp]

📝 Description

Build a public resolver page at /resolve or /@username where anyone can look up an Alien Gateway username and see its linked Stellar address and external chain addresses. This is the shareable profile link for every registered user.

✅ Requirements

• URL format: /@username or /resolve?name=username
• Input: username search bar
• Calls SDK resolveUsername — shows Stellar address + memo (if set)
• Shows linked external chain addresses (EVM, BTC, Solana) if any
• Copy-to-clipboard button for each address
• "Send payment" button that prefills Stellar payment with resolved address + memo
• 404 state for unregistered usernames

🎯 Acceptance Criteria

• Page resolves @username to Stellar address via SDK
• Linked chain addresses displayed with chain icons
• Copy button works for each address
• "Send payment" button deep-links into Freighter or a Stellar pay URL
• 404 state shows clear "username not registered" message
• Mobile responsive

📁 Expected files to change/structure

• src/pages/[username].tsx or src/pages/resolve.tsx
• src/components/AddressCard.tsx
• src/components/ResolverSearch.tsx
• src/hooks/useResolver.ts

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🌿 Branch: feat/web-resolver-page | Priority: MED | Difficulty: ☕☕ medium