feat: Phase 7 — Node v2 (multi-group, Sender Keys, 0-RTT, chat, denylist)

Implements all 8 milestones (7.0-7.7):

- 7.0: JWT carries `groups` claim; node verifies group membership at
  MNP handshake (QUIC + TCP+TLS). Resolves security review C2.
- 7.1: QUIC 0-RTT session resumption via stored session tickets
  (17-21ms reconnect vs 47ms cold).
- 7.2: Hub→node WebSocket signaling for NAT punch coordination
  (`client_incoming`/`punch_ready`) + jti denylist push. Denylist
  class blocks revoked users/jtis at handshake.
- 7.3: Multi-group daemon — one QUIC port serves N groups with
  per-group GEK, shared_root, and index routing.
- 7.4: HLS streaming via QUIC (STREAM_SEGMENT message type, ffmpeg
  segment extraction).
- 7.5: Sender Keys protocol for group chat (Signal Groups approach).
  Each member has own sending chain key, HKDF chain ratchet, AES-256-GCM
  encryption, Ed25519 signing. Resolves security review C1.
- 7.6: Chat store (SQLite via aiosqlite), CHAT_MESSAGE MNP wire type
  with peer broadcast, web UI with WebSocket push.
- 7.7: Argon2id calibration CLI.

First security review included (first-review.md). 109 tests, demo-v3
validated against meshbay.org production hub.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/auth.py b/packages/meshbay-hub/src/meshbay_hub/auth.py
index a4c3bfb..2b2c61e 100644
--- a/packages/meshbay-hub/src/meshbay_hub/auth.py
+++ b/packages/meshbay-hub/src/meshbay_hub/auth.py
@@ -105,10 +105,12 @@ def issue_access_token(
     user_id: str,
     pk_user: str,
     ttl: int = 3600,
+    groups: list[str] | None = None,
 ) -> str:
     """
     Issue a signed JWT access token.
     Includes jti (UUID4) — required to prevent replay and enable revocation.
+    Includes groups — list of group_ids the user is a member of (node-side authz).
     """
     if _hub_sk_pem is None:
         raise RuntimeError("Hub keypair not loaded")
@@ -121,6 +123,7 @@ def issue_access_token(
         "jti":     str(uuid.uuid4()),
         "iat":     now,
         "exp":     now + ttl,
+        "groups":  groups or [],
     }
     return jwt.encode(payload, _hub_sk_pem, algorithm="EdDSA")