fix(frontend): remove unsafe non-null assertion on WalletConnect publicKey

[VedantMadane]

Description

WalletConnect.tsx used publicKey! when rendering the connected wallet UI. If status is connected but publicKey is unexpectedly null/undefined, that assertion would throw at runtime.

This change:

• Guards on publicKey before truncating/rendering the address
• Shows an Address unavailable fallback (and still allows Disconnect)
• Logs a console.warn in dev mode for the edge case
• Adds unit tests covering connected-with-key, connected-without-key, and disconnected states
• Bumps frontend patch version 0.1.0 → 0.1.1

Related Issues

Fixes #274

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation
• Infrastructure / tooling

Testing Done

cd frontend
npm ci
npx vitest run src/components/WalletConnect.test.tsx
# ✓ 3 tests passed

Pre-existing baseline npm run typecheck / full suite failures are unrelated to this change.

Checklist

• Code follows the project's style guidelines
• Tests pass locally (WalletConnect suite)
• Documentation updated (N/A — internal null-safety fix)
• No breaking changes without prior notice in the description above