## 1. Red conformance

- [x] 1.1 Add fixed datagram-v2 and capability vectors that fail current Python, Go, Rust, and Swift validators
- [x] 1.2 Prove unknown version, malformed length, invalid fragment, and oversized complete-unit cases remain rejected

## 2. Contract implementation

- [x] 2.1 Add the versioned datagram-v2 frame grammar and registered framing values
- [x] 2.2 Update generator/native validators and regenerate Go, Rust, and Swift bindings normally

## 3. Verification

- [x] 3.1 Run focused cross-language conformance and strict OpenSpec validation
- [x] 3.2 Run complete `make verify` and prove a second generation has no drift

## 4. Immutable boundary

- [x] 4.1 Publish one new never-reused immutable Protocol version, resolve it
  from separate empty consumer caches, and pin the fetched checksums in both
  consumers