Lodestone Protocol (MD-DAG) v1.3.0

Lodestone Protocol — Markdown‑Embedded DAG for conversational knowledge convergence / Alias: MD‑DAG
v1.3.0 — Official protocol release (this repository holds the authoritative specification; lodestone‑md is the Rust reference implementation).

• Full specification: spec/v1.3.md (§8.1 auxiliary‑field permissive patch + 14‑code registry at registry/errors.md)
• Golden Fixture corpus: 25 sets (under fixtures/, with MANIFEST chapter index). Expected output bytes are normative per the specification.
• Frozen items: syntax identifier mddag, §8.1‑8.4 output contracts, §3.1 behavior table, the 14 error/warning codes.
• License: Apache‑2.0