chore: verify generated protocol sources

[benbrandt]

Summary

• add an offline generation check for committed v1 and v2 sources
• verify metadata protocol versions and method sets against schema x-method declarations
• run generated-source verification in local checks and CI
• ignore generated TypeDoc output during lint so checks remain repeatable after docs builds

Schema downloads remain pinned to the existing releases; this does not add another protocol lane.

Testing

• npm run generate:check
• negative stale-file probe
• npm run check (834 tests)