feat: implement version registry and name-service event metadata (#403)

[Tekgodfrey]

• Dual emit tls_crt2 and name_reg2 events with schema version alongside old events
• Add UnsupportedVersionError to off-chain TypeScript parser
• Update event fixtures and tests to verify decoding and rejection of unsupported versions
• Document new events and fix fee_chg table formatting in README.md

Summary

This PR addresses the need for the on-chain event consumers to be resilient to future contract schema changes without breaking the existing indexing infrastructure. It implements a dual-emission strategy for the talos_registry and talos_name_service contracts, where version-aware events (tls_crt2 and name_reg2) are now emitted alongside the original tls_crt and name_reg events. A new version field (u32) was explicitly added to these v2 payloads.

Furthermore, strict rejection handling (UnsupportedVersionError) was added to the TypeScript off-chain decoder in event-query.ts to ensure that it explicitly rejects any event version it doesn't recognize rather than attempting to decode it with outdated schema logic.

Related Issues

Closes #403

Test Plan

• Automated tests run:
  • cargo test executed in contracts/talos_registry (76/76 tests passing).
  • cargo test executed in contracts/talos_name_service (42/42 tests passing).
  • pnpm --dir contracts test:fixtures executed (36/36 tests passing).
• Manual verification steps performed:
  • 1. Hand-crafted a malformed event fixture with an unsupported version (version: 2) inside event_fixtures.json.
  • 2. Verified that the TypeScript indexer correctly throws an UnsupportedVersionError when iterating over the new malformed fixture.
• Relevant docs updated when setup, environment variables, or workflows changed (Updated README.md and EVENTS.md with new schema properties).

Visual Changes (if applicable)

N/A (Backend / Smart Contract event schema updates only)

Checklist

• I have read the CONTRIBUTING.md guide.
• My code follows the style guidelines of this project.
• I have updated .env.example files and documentation if I changed environment variables.
• My changes generate no new warnings or errors.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

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