boneyard v0.1.2 — pure Rust + std:: only

boneyard v0.1.2 — pure Rust + std:: only

No code changes; this is a documentation cleanup to match the studio2201 framework v0.1.2 release.

• README.md rewritten to drop openOODA substrate references (seance / opm / bb / ML-DSA-65 / Merkle-AST mentions removed where they described the implementation path). The 'same family as Vigil' framing now points at the pure-Rust + std:: style instead of a shared substrate.
• CHANGES.md updated with a [0.1.2] entry.

The framework now explicitly states that there is no substrate — pure Rust + std::* only.