feat(l0): implement Noise Protocol Framework with MIMIC integration
Add complete Noise Protocol implementation (noiseprotocol.org):
- NoiseState with X25519, ChaCha20-Poly1305
- Patterns: XX (mutual auth), IK (0-RTT), NN (ephemeral)
- CipherState for transport encryption
- NoiseHandshake with MIMIC skin integration
Add comprehensive BDD feature tests:
- noise_protocol.feature with 40+ scenarios
- Tests for handshake, security properties, PNG integration
Update RFC-0015:
- Add Noise Protocol integration section
- Architecture diagram showing Noise + PNG + MIMIC layers
- Update implementation phases
All tests passing
9b1a1d6736
