Dogfooding E2E Proof for Full-Chain Traceability

[djm81]

Why

The dogfooding proof should demonstrate both end-to-end traceability and clean-code compliance in one governed evidence bundle.

What Changes

• Keep the end-to-end backlog -> requirement -> architecture -> spec -> code/test -> evidence proof path.
• Add clean-code review output to the final proof bundle.
• Treat clean-code regressions as release-readiness failures for the dogfood proof chain.

OpenSpec Change Proposal: dogfooding-01-full-chain-e2e-proof

[djm81]

Dependency mapping from CHANGE_ORDER: blocked by #239, #240, #241, #242, #247.