Verify the complete WebMCP authoring journey

[ErickWendel]

Closes #178

Summary

• documents the shipped 15-tool authoring catalog, setup, architecture, judge flow, and attendee roadmap
• verifies create, exact multi-batch authoring, inspection, descriptions, translation, export, publishing, transcript context, and authorized raw audio
• fixes native browser execution by serializing WebMCP input arguments and parsing serialized results
• preserves the authored revision through public-share sanitization while excluding unauthorized raw audio

Verification

• npm run lint (one pre-existing unused-disable warning)
• npm run typecheck
• npm test (934 passed, 4 skipped across workspaces)
• npm run build
• npm run test:e2e:coverage:webmcp (4 passed)
• focused native showcase and production authoring Playwright suite (4 passed)
• two independent code-review passes with no remaining findings