[chubes4]

Summary

The virtual base route forced private page-marker variants into costly route scopes. Shared template-part markup now supplies conservative carrier evidence, allowing private variants to remain unscoped without weakening render-time state or non-plan page correctness.

What changed

• Pass shared template-part candidates into virtual-base and plan-route inertness proofs.
• Recognize required page-local classes in selector subjects and ancestors using token/carrier checks.
• Keep plain arms and render-time route-state selectors scoped when required.
• Extend the existing scaling contract for private markers, shared-header carriers, and roughly constant site-wide stylesheet size.
• Additive. Route hooks, stylesheet byte budgets, fallback policy, and no-route-class base behavior remain unchanged.

Verification

• cd php-transformer && php tests/unit/css-stylesheet-transformer.php passed on d2ffcec. Base trunk@e0393f3 advanced to 3f37b9d.

• cd php-transformer && php tests/contract/shared-author-stylesheet-scaling.php passed on d2ffcec. Base trunk@e0393f3 advanced to 3f37b9d.

• cd php-transformer && php tests/unit/document-root-font-ownership.php passed on d2ffcec. Base trunk@e0393f3 advanced to 3f37b9d.

• cd php-transformer && composer test:canonical passed on d2ffcec. Base trunk@e0393f3 advanced to 3f37b9d.

• cd php-transformer && composer lint passed on d2ffcec. Base trunk@e0393f3 advanced to 3f37b9d.

• CI: pending

Cook run

• Gate 1: tree ba2b73003db03c7851af69a0a4068b952a69d1b3, fingerprint e4d86c46c58f0ee9c8bf926ba199dbd47f178ee713f7d13b699358a4876e8fbc
• Gate 2: tree ba2b73003db03c7851af69a0a4068b952a69d1b3, fingerprint e4d86c46c58f0ee9c8bf926ba199dbd47f178ee713f7d13b699358a4876e8fbc
• Gate 3: tree ba2b73003db03c7851af69a0a4068b952a69d1b3, fingerprint e4d86c46c58f0ee9c8bf926ba199dbd47f178ee713f7d13b699358a4876e8fbc
• Gate 4: tree ba2b73003db03c7851af69a0a4068b952a69d1b3, fingerprint e4d86c46c58f0ee9c8bf926ba199dbd47f178ee713f7d13b699358a4876e8fbc
• Gate 5: tree ba2b73003db03c7851af69a0a4068b952a69d1b3, fingerprint e4d86c46c58f0ee9c8bf926ba199dbd47f178ee713f7d13b699358a4876e8fbc
• Publication identity: ambient_gh

AI assistance

Tool: Homeboy (pi) · Model: gpt-6.1-sol (tier roadie/cook-heavy) · Used for: AI inspected the PR and linked design discussion, implemented carrier-based proofs, extended regression coverage, and ran all required gates.

Relates to #3548