release: explorer SDK 5.0.1 transaction chain validation

[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]

Release review: main...dev is the same independently reviewed three-file dependency/example update from PR #191. Local clean-install, all 575 tests, lint, TypeScript, formatting, API drift, and full production build gates pass. Staged release includes only the frontend, preserves the API/synchronizer and database, and retains the previous frontend for rollback.