ANL-253 Automate Intercom support article screenshots

[eloywijlhuizen-zeno]

Summary

• vendor the clean installed Zeno support-skill baseline and add a validated, backup-first atomic installer
• add the capture-zeno-support-screenshots skill for Browser-only synthetic demo-tenant capture and local visual approval
• extend the article helper with structured screenshot plans, PNG/hash validation, review galleries, approval invalidation, placeholder staging, upload locks, and read-back reconciliation
• integrate the writer and manager handoffs through manual Intercom editor upload with exact alt text
• normalize documented Intercom image wrappers and signed-CDN URL changes while rejecting changed prose, metadata, state, image order, hosts, alt text, or PNG bytes

Linear: ANL-253

Validation

• 19/19 draft and screenshot workflow tests
• 13/13 manager, legal, approval, and concurrent-claim tests
• 3/3 installer tests
• 5/5 packaged skill validators
• 5/5 screenshot CLI help surfaces
• fresh-agent fixture forward test passed
• installer dry-run and post-commit local installation hash verification passed
• ruff E/F checks and git diff --check passed

Manual acceptance

• With explicit approval, run the end-to-end flow against the configured synthetic demo tenant and a sacrificial Intercom draft: capture, approve, stage placeholders, manually insert images and alt text, reconcile, and confirm the target remains a verified draft.

The live acceptance is intentionally not automated by this PR because the workflow requires exact approved demo origin/sentinel values and a dedicated approval for the sacrificial Intercom draft write.