fix(frontend): harden SDK wallet lifecycle

[moscowchill]

Summary

• require exactly one current-format Q plus 40-hex wallet account
• explicitly authorize fresh relay pairings while reusing only valid reconnect caches
• serialize wallet selection and bind async completion to the active attempt and relay channel
• ignore SDK teardown events only during guarded channel rotation
• require confirmed relay retirement before extension activation and surface all retirement failures
• move the BrowserRouter SPA to patched React Router 8.3.0 with its React and Node floors
• pin the audited registry releases exactly: @qrlwallet/connect 4.0.0 and @qrlwallet/connect-ui 0.2.0

Validation

• clean npm install from the public registry
• installed SDK and UI versions and lockfile integrities verified against the audited release artifacts
• zero-warning frontend lint
• 10 lifecycle and address tests
• TypeScript and production Vite build
• Solidity format and size build
• 226 Foundry tests
• 29 deployment-safety tests
• npm audit: 12 known low web3 findings, with zero moderate, high, or critical findings

Release gate

Completed. SDK 4.0.0 and UI 0.2.0 are published, exact-pinned, integrity-verified, and validated from a clean registry install.