🚨[Hotfix] Restore v2.1.0 production deployment

[maruson08]

Problem

The v2.1.0 deployment artifact now contains 20 public and migration index.html files after adding Image → Text, but the production workflow still required exactly 19. Recovery run 36149417605 therefore failed in Prepare isolated bridge artifact before any Cloudflare upload.

GitHub also emitted no PushEvent for release merge 45e404db24fa16f429eb63c000ef4d550d83c576, which explains why no automatic run initially appeared.

Fix

• Update the deployment artifact invariant from 19 to 20 pages.
• Assert the workflow page count in the existing Cloudflare bridge contract test.
• Preserve all product code, branch policy, commit validation, PR-title validation, and deployment isolation controls.

Validation

• node tests/cloudflare-bridge.test.mjs
• npm test
• git diff --check
• Commit and PR-title convention validation

Closes #86