fix(connect): pin explorer and example to SDK 5.0.1

[moscowchill]

Summary

Pin the explorer and hosted dApp example to QRL Connect 5.0.1. This patch accepts an explicitly pinned transaction chain ID and revalidates queued transactions against the current account and network before transport.

Validation

• Clean npm ci and audit: zero vulnerabilities.
• All 575 frontend tests pass, including contract-write chain and genesis guards.
• ESLint: zero errors and 14 existing warnings. TypeScript, Prettier, API drift and shell syntax checks pass.
• Full production build and hosted example build from public tag v5.0.1 pass.
• Published package integrity matches the independently tested release artifact.
• Independent review of the three-file diff passed. No transitive dependency changes.

Release scope

Frontend rebuild and restart only. No database, API, synchronizer, network or reverse-proxy changes. Existing chain and genesis guards remain enabled. The optional contract verifier retains its existing fail-closed availability state.

[moscowchill]

Independent review completed: the three-file diff only changes the exact SDK pin, registry artifact integrity, and hosted example tag. No transitive dependency churn or source findings. Local release gates pass: 575 tests, zero lint errors, TypeScript, Prettier, API drift, full production and hosted example builds, and zero audit vulnerabilities. Deployment remains frontend-only with the previous frontend retained for rollback.