feat(protocol): MNP 4.0 flag day for the node-audience token (B2)

The node-audience token (previous commit) is a change to what a peer must
present, so it is a MAJOR per the versioning rule (§5.6): a pre-4.0 client
presents its hub session token and a 4.0 node refuses it, and there is no
compatibility branch, because leaving one would keep a hub credential reachable
by every node (C6's lesson). So the floor moves with the version.

- MNP_VERSION 3.4 -> 4.0 and MNP_MIN_SUPPORTED 3.0 -> 4.0 (meshbay_common);
  transport.js MNP_V/MNP_V_MIN -> 4.0 to match.
- MIN_CLIENT_VERSION 0.13.0 -> 0.16.0 so a stale desktop client is told to
  update before connecting rather than meeting a handshake refusal it cannot
  read; the browser reloads this build from the hub.
- Regenerate tests/golden/dispatch.json: the only change is the `v` the node
  stamps on outbound messages, 3.4 -> 4.0 (56 cases, v field only).
- Document the split and the flag day: MESHBAY_DESIGN.md §5.2 (the handshake
  token is the MNP-audience token), §5.6 (the 4.0 flag day), register E10 and
  decision 23; MESHBAY_NODE_PROTOCOL.md §6.3 (authorize_token binds MNP_AUD)
  and the wire-version banner.

Deploy is coordinated and atomic (common+hub+node+SPA together); a live
browser-to-node validation and the deploy itself remain. common (173), node
(1489, the pre-existing test_cli_golden argparse/prog artifact aside) and hub
(1471) suites all green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 56 insertions, 56 deletions

diff --git a/packages/meshbay-node/tests/golden/dispatch.json b/packages/meshbay-node/tests/golden/dispatch.json
index 98911f5..5d15057 100644
--- a/packages/meshbay-node/tests/golden/dispatch.json
+++ b/packages/meshbay-node/tests/golden/dispatch.json
@@ -2228,7 +2228,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2551,7 +2551,7 @@
      "subject": "gggggggggggggggggggggggggggggggg",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2570,7 +2570,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2589,7 +2589,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2608,7 +2608,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2878,7 +2878,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2892,7 +2892,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2906,7 +2906,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2920,7 +2920,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2934,7 +2934,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2948,7 +2948,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2962,7 +2962,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -2976,7 +2976,7 @@
      "messages": [],
      "req_id": 4242,
      "type": "chat_hist_resp",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -8855,7 +8855,7 @@
      "subject": "gggggggggggggggggggggggggggggggg",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -8874,7 +8874,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -8893,7 +8893,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -8912,7 +8912,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -9247,7 +9247,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -9266,7 +9266,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -9285,7 +9285,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -9620,7 +9620,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -9639,7 +9639,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -9658,7 +9658,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -11961,7 +11961,7 @@
      "subject": "link:gggggggggggggggggggggggggggggggg",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -14060,7 +14060,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -14079,7 +14079,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -14098,7 +14098,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -14433,7 +14433,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -14452,7 +14452,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -14471,7 +14471,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16532,7 +16532,7 @@
      "req_id": 4242,
      "token": null,
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16547,7 +16547,7 @@
       "x"
      ],
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16560,7 +16560,7 @@
      "req_id": 4242,
      "token": 7,
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16573,7 +16573,7 @@
      "req_id": 4242,
      "token": "x",
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16586,7 +16586,7 @@
      "req_id": 4242,
      "token": null,
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16601,7 +16601,7 @@
       "x"
      ],
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16614,7 +16614,7 @@
      "req_id": 4242,
      "token": 7,
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16627,7 +16627,7 @@
      "req_id": 4242,
      "token": "x",
      "type": "pong",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16962,7 +16962,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -16981,7 +16981,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17000,7 +17000,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17335,7 +17335,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17354,7 +17354,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17373,7 +17373,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17708,7 +17708,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17727,7 +17727,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -17746,7 +17746,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -18081,7 +18081,7 @@
      "subject": "['x']",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -18100,7 +18100,7 @@
      "subject": "7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -18119,7 +18119,7 @@
      "subject": "x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -18454,7 +18454,7 @@
      "subject": "['x']:rw=on,rem=on",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -18473,7 +18473,7 @@
      "subject": "7:rw=on,rem=on",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -18492,7 +18492,7 @@
      "subject": "x:rw=on,rem=on",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -21439,7 +21439,7 @@
      "subject": "custom_token=no,language=default",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -21482,7 +21482,7 @@
      "subject": "custom_token=yes,language=x",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []
@@ -23369,7 +23369,7 @@
      "subject": "d=7,u=7",
      "ts": "<volatile>",
      "type": "admin_challenge",
-     "v": "3.4"
+     "v": "4.0"
     }
    ],
    "spawned": []