fix: harden workflow authority gates

[freshtechbro]

Summary

• Harden workflow completion paths so transport success does not imply authority success.
• Preserve Pinterest pin-media as the authority gate while keeping media-analysis advisory and login/challenge diagnostics blocked.
• Surface useful readiness states for research, shopping, product-video, macro execution, docs, skills, and generated public surface.

Verification

• npm run lint
• npm run typecheck
• npm run build
• npm run test, 302 test files passed, 5826 tests passed, branch coverage 97.01%
• npm run extension:build
• npm run version:check
• node scripts/docs-drift-check.mjs
• Authority smoke proof: /tmp/opendevbrowser-authority-final-gates/workflow-authority-smoke-proof-after-fixes.md
• Final gate: /tmp/opendevbrowser-authority-final-gates/final-quality-gate.json

Authority Smoke Results

• Inspiredesign snapshot: product-ready with evidenceAuthority=snapshot_ready.
• Pinterest default harvest: product-ready with evidenceAuthority=pin_media_ready.
• Research auto: usable public-first web,community output.
• Shopping and product-video: completed with explicit partial readiness and review guidance.
• Macro execute: complete execution with meta.ok=true, partial=false, failures=0.