Implement beta8 compiler functionality gate

[brik64-admin]

Summary

• replaces the unsigned beta8 candidate branch with one signed commit for branch-policy compliance
• adds bounded PCD source-to-source emission for executable JS/TS, Rust, and Python targets
• adds beta8 compiler functionality, adversarial, local package, package smoke, and release-train dry-run evidence
• keeps release manifest in draft state; public release remains blocked until public-surface gates pass

Validation

• npm run gate:beta8:compiler-functionality
• npm run gate:beta8:adversarial
• npm run package:beta8:local
• npm run smoke:beta8:package
• npm test
• npm run release:train:dry-run -- --allow-dirty

Claim boundary

This is a bounded beta8 candidate. It does not claim public release readiness, formal N5 status, fixpoint, self-hosting, Rust independence, or universal correctness.

[carlosjperez]

Reviewed signed beta8 replacement PR. Approval covers bounded compiler functionality, adversarial gate, local package smoke, and release-train dry-run only; public release remains blocked until public-surface gates pass.

[brik64-admin]

Superseded by PR #65, which carries the beta8 compiler candidate plus the GitHub verified-signature release gate. Keeping beta8 public release blocked until the signing key is registered and the gate passes.

[brik64-admin]

Closed as superseded by PR #65. No admin override used; beta8 remains blocked on GitHub verified signing identity.