feat: add digest-bound workload policy envelope

[ZhiXiao-Lin]

Summary

• add a bounded, canonical native-ACL policy envelope using a3s-acl 0.3.0
• bind policy bytes to workload, revision, replica, node, positive generation, and SHA-256 digest
• reject noncanonical wire bytes, malformed metadata, tampering, identity/digest mismatches, stale/future generations, and oversized producer output
• document the admission contract, readiness boundary, and current node-global enforcer limitation

This is the first bounded slice of #2. It intentionally leaves the umbrella issue open: typed egress/exec/file capability enforcement, atomic and restart-safe apply state, workload readiness gating, and structured audit evidence remain follow-up work.

Validation

• cargo fmt --all -- --check
• strict Clippy and all Rust tests on stable and Rust 1.88.0
• 72 unit + 13 daemon integration + 7 policy contract tests
• doctests and warning-free rustdoc
• cargo package --allow-dirty
• TypeScript native SDK build + 12 tests
• Python 3.9 native SDK build + 15 tests
• locked dependency metadata for both SDK manifests