refactor(node): move the session core out of webrtc_server

SessionCore in transport/webrtc/core.py, last among the bases: state,
the data channel, task ownership, the peer registry, sending and teardown.
The facade keeps _dispatch_message and WebRTCTransport.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 7 insertions, 6 deletions

diff --git a/docs/MESHBAY_NODE_PROTOCOL.md b/docs/MESHBAY_NODE_PROTOCOL.md
index 35366f0..a219b50 100644
--- a/docs/MESHBAY_NODE_PROTOCOL.md
+++ b/docs/MESHBAY_NODE_PROTOCOL.md
@@ -4,8 +4,8 @@
 **Oldest peer accepted:** `3.0` — `handshake.py` (`MNP_MIN_SUPPORTED`)
 **Normative implementation:** `meshbay-common` (`protocol.py`, `handshake.py`,
 `groupbox.py`, `chatbox.py`, `adminop.py`, `join.py`, `device.py`, `crypto.py`,
-`webcrypto.py`), `meshbay-node` (`transport/wire.py`, `transport/webrtc_server.py`,
-`transport/quic_server.py`, `transfers.py`, `uploads.py`), browser client
+`webcrypto.py`), `meshbay-node` (`transport/wire.py`, `transport/webrtc_server.py`
+and `transport/webrtc/`, `transport/quic_server.py`, `transfers.py`, `uploads.py`), browser client
 (`meshbay-hub/static/transport.js`, `static/crypto.js`).
 **Document status:** descriptive specification of the protocol as implemented on
 2026-09-10. It describes the protocol as it stands. Where the code and this document
@@ -2291,7 +2291,7 @@ LP(x) = uint32be(len(x)) || x        every field, no exceptions
 | Device attempts | 5 per connection | ” |
 | `MAX_DEVICES_PER_USER` | 5 | `roster.py` |
 | `MAX_LINK_INVITES_PER_GROUP` | 20 unredeemed invitation links | `roster.py` |
-| `PRE_HANDSHAKE_MAX_MSG` / `MAX_MSG` | 64 KiB / 64 MiB | `webrtc_server.py` / `webrtc/limits.py` |
+| `PRE_HANDSHAKE_MAX_MSG` / `MAX_MSG` | 64 KiB / 64 MiB | `webrtc/core.py` / `webrtc/limits.py` |
 | `CHUNK_SIZE` | 1 MiB | `webrtc/limits.py` |
 | `DOWNLOAD_BUFFER_HIGH` | 2 MiB | `webrtc/files.py` |
 | `MAX_UPLOAD_BYTES` | 8 GiB, default only — `max_upload_gb` overrides it per node | `webrtc/upload_handlers.py` |
@@ -2301,7 +2301,7 @@ LP(x) = uint32be(len(x)) || x        every field, no exceptions
 | `UPLOAD_PROBE_INDEX` / probe timeout | `-1` / 5 s | `protocol.py`, `transport.js` |
 | `PART_SUFFIX` / `ORPHAN_AFTER_SECS` | `.part` / 24 h | `uploads.py` |
 | `DEFAULT_MAX_CONCURRENT` (node-wide, per kind) | 8 | `transfers.py` |
-| `DEFAULT_MAX_PER_MEMBER` (per group, per kind) | 2, settable 1–32 | `transfers.py`, `webrtc_server.py` |
+| `DEFAULT_MAX_PER_MEMBER` (per group, per kind) | 2, settable 1–32 | `transfers.py`, `webrtc/node_ops.py` |
 | `GRANT_DEADLINE_SECS` / `IDLE_TIMEOUT_SECS` | 30 s / 120 s | `transfers.py` |
 | `MAX_QUEUED_PER_MEMBER` / `MAX_MISSED_GRANTS` | 32 / 3 | ” |
 | `MAX_LEASELESS_IN_FLIGHT` / `LEASELESS_IDLE_SECS` | 12 files / 60 s | ” |
@@ -2340,7 +2340,8 @@ meshbay-common/   protocol.py      message types, chunk and upload codecs
                   crypto.py        GEK, chunk keys, ECIES wrap, BLAKE3 ids
                   webcrypto.py     the AES variants the browser can also compute
 
-meshbay-node/     transport/webrtc_server.py   the reference implementation of MNP
+meshbay-node/     transport/webrtc_server.py   the reference implementation of MNP,
+                  transport/webrtc/            assembled from these modules
                   transport/quic_server.py     the QUIC transport, in development (§5.2)
                   transport/wire.py            the one index encoder
                   transfers.py                 leases, queues, caps, leaseless reads
diff --git a/docs/transfers-v1.md b/docs/transfers-v1.md
index f1002a9..47e82a6 100644
--- a/docs/transfers-v1.md
+++ b/docs/transfers-v1.md
@@ -181,7 +181,7 @@ node-wide slot they would then hold while a second member has none. Reversed,
 one member arriving first takes all eight.
 
 **"Per member" means per account, summed across their devices**, resolved with
-`_sessions_of(user_id)` (`webrtc_server.py:3325`) — which exists for exactly
+`_sessions_of(user_id)` (`webrtc/core.py`) — which exists for exactly
 this reason, since device linking landed. Two browsers and a desktop client
 signed in as the same person share the two slots. Anything else makes the cap a
 function of how many tabs someone opens.