merge: Phase 11.5 security remediation, invite redesign, per-node identity

Brings in the security remediation branch. Three bodies of work, and what they
changed about what this project may claim.

Phase 11.5 closed the gap between the documents and the code: the unauthenticated
node HTTP API and the TCP transport deleted, one handshake shared by the
remaining two transports, mutual authentication, structured admin transcripts,
upload confinement, group isolation, revocation that reaches nodes. Six critical
and seven high findings closed, bounded, or deferred by decision.

The invite redesign closed H3 and M3 — the last open High. The hub was the key
directory: an inviter fetched the invitee's key from it and wrapped the group key
for whatever came back, so a hub answering with its own key was handed the group
key by an honest member following the protocol exactly. That lookup is gone. The
node holds the group key and wraps it itself, for a key its recipient proves
possession of, bound to an account by a one-time code the hub never sees. M3 fell
out of the same work: node authority comes from a local roster, never from the
hub.

Per-node identity cut what remains of C4 down to one operator. A single keypair
used to be copied to every node its owner joined; each node now gets its own, so
cracking the bundle on one machine yields a key that is a stranger everywhere
else — and on that machine, one that unlocks nothing its holder did not already
serve. The bundle KDF moved to Argon2id 128 MB, and the hub stopped storing or
publishing user keys at all.

What this project may now say: the hub cannot read your content unless it ships
you malicious client code. T3 remains, accepted (D1), and is what the native
client removes. C4 is reduced, not closed, until 13.3. Chat is still plaintext at
rest until Phase 15. Draft-v5 §2 states each claim against the adversary it holds
against, which is the convention this branch exists to keep.

Four defects were found by deploying it and using a browser, none by the test
suite: a node going deaf on its hub socket, a token that predated group
membership, a client reading values before they were assigned, and identity keys
a browser held but never re-read. The lessons are recorded in CLAUDE.md.

Tests: 343 across the three packages, plus QE/deploy/e2e.py — register, pair,
invite, join, download, stream, second browser, revoke — run against the live
deployment on a wiped hub and node.

1 files changed, 15 insertions, 6 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/transport/__init__.py b/packages/meshbay-node/src/meshbay_node/transport/__init__.py
index df9c209..e423e35 100644
--- a/packages/meshbay-node/src/meshbay_node/transport/__init__.py
+++ b/packages/meshbay-node/src/meshbay_node/transport/__init__.py
@@ -1,7 +1,17 @@
-"""MeshBay Node transport layer — TCP+TLS (v1), QUIC (v2), WebRTC (browsers)."""
-from .server import ChunkServer
-from .client import ChunkClient
-from .http_server import create_http_app
+"""
+MeshBay Node transport layer — WebRTC DataChannel (primary), QUIC (direct/LAN).
+
+Transport decision (2026-08-13, second security review):
+  - WebRTC/ICE is the primary path for browser AND native clients. ICE/STUN is the
+    only NAT traversal validated on this project (2 ISPs, IPv4 STUN + IPv6, 4G CGNAT).
+  - QUIC is kept at parity for LAN, port-forwarded and hub-less `group://` access.
+    `punch_nat()` is a direct-connection helper, not a traversal stack.
+  - TCP+TLS (`server.py`/`client.py`) and the node HTTP file API (`http_server.py`)
+    were REMOVED in Phase 11.5. The HTTP API served private group indexes and
+    plaintext files with no authentication on 0.0.0.0 (finding C1); the TCP server
+    accepted a bare JWT with no GEK proof (finding C6). Neither is coming back —
+    every client path must go through the unified MNP handshake.
+"""
 
 # QUIC transport (MNP v2) — requires aioquic>=1.0
 try:
@@ -14,7 +24,7 @@ except ImportError:
     Denylist = None  # type: ignore[assignment,misc]
     QUIC_AVAILABLE = False
 
-# WebRTC transport (browsers) — requires aiortc>=1.9
+# WebRTC transport (browsers + native clients) — requires aiortc>=1.9
 try:
     from .webrtc_server import WebRTCTransport, WebRTCPeerSession
     WEBRTC_AVAILABLE = True
@@ -24,7 +34,6 @@ except ImportError:
     WEBRTC_AVAILABLE = False
 
 __all__ = [
-    "ChunkServer", "ChunkClient", "create_http_app",
     "QuicChunkServer", "QuicChunkClient", "Denylist", "QUIC_AVAILABLE",
     "WebRTCTransport", "WebRTCPeerSession", "WEBRTC_AVAILABLE",
 ]