ruview @ v1228

Automated release from CI pipeline

Changes: cog-ha-matter (ADR-116 P4): Ed25519 signing layer for witness chain

Closes the cryptographic-attestation gap in ADR-116 §2.2: every witness event can now be signed by the Seed's Ed25519 key, with verify available to any auditor holding the public key.

Module shape (src/witness_signing.rs, kept separate from witness:: so the hash chain stays usable without dalek linked in — important for the wasm32 audit-verifier variant we'll ship later):

• sign_event(event, &SigningKey) -> Signature
• verify_signature(event, &Signature, &VerifyingKey) -> Result<(), SignatureVerifyError>
• signature_to_hex / signature_from_hex (128-char lowercase, matches the witness hex convention)
• SignatureVerifyError::Invalid
• SignatureParseError::{Length, Hex}

Key design point: signature covers the SAME canonical bytes witness::hash_event hashes. That means:

1. A signed event commits to the entire event content (kind, payload, timestamp, seq, prev_hash) — no field can be retroactively changed without invalidating both the hash AND the signature.

2. The signature implicitly commits to the event's chain position via prev_hash — splicing a signed event into a different chain breaks verification.

Adds ed25519-dalek = "2.1" to cog-ha-matter (already in workspace via ruv-neural, version kept aligned).

9 new tests:

• sign_and_verify_round_trip
• verify_rejects_signature_under_wrong_key
• verify_rejects_tampered_event (mutate payload after sign)
• verify_rejects_event_with_wrong_prev_hash (splice attack)
• signature_hex_round_trip
• signature_from_hex_rejects_wrong_length
• signature_from_hex_rejects_non_hex
• signature_is_deterministic_for_same_event_and_key (locks Ed25519's determinism — catches future accidental swap to a randomized scheme)
• different_events_produce_different_signatures

60/60 cog tests green (51 → 60). Key management is intentionally out of scope here — the cog runtime reads the Seed's key from the Cognitum control plane's secure store (separate concern).

ADR-116 P4 now ⁵⁄₆: ✅ mDNS record, ✅ chain, ✅ JSONL, ✅ file persistence, ✅ Ed25519 signing; ⏳ responder + embedded broker.

Co-Authored-By: claude-flow ruv@ruv.net

Docker Image: ghcr.io/ruvnet/RuView:bb154d4e7808622aff34bfea79a1b8d4f3021a61