Merge branch 'fix/large-download-paths'

Concurrent-transfer limits, with the queue, the pause and the flag day.

A node now caps how many transfers it runs at once (8 downloads, 8 uploads,
node-wide) and how many one member may run in one group (2 by default,
operator-signed). Beyond that the node answers "queued" and the client waits its
turn, visibly, in the transfers panel — and a slot that frees starts whatever is
next, skipping past a member who is at their own cap rather than letting them
stall everyone behind them.

Browsing is never subject to a slot: not the poster grid, not the covers, not
opening a photo to look at it. That is structural — a transfer is what the
transfers widget shows — and the exemption is bounded rather than open, at two
files in flight per session, because an exemption with no bound is a leaseless
branch under another name.

Transfers can be cancelled, and now paused and resumed. A paused one holds
nothing: its slot goes back at once and resuming rejoins the queue at the tail.
Uploads survive the connection that started them and resume where the node
stopped, asked for inside the seal rather than on a clear message. What they
leave behind when they are abandoned is reaped, which closes a disk leak that
predates this work.

MNP 3.0 makes the lease compulsory and refuses 2.x at the handshake, with the
desktop client checking `client.minimum` before connecting so an un-updated one
says "update" instead of failing every connection in a protocol vocabulary.

Fourteen defects were found on the way, eight of them by a person clicking
Download and pasting a console — none of which 2075 tests could reach. Section
12 of ~/next/improve-downloads.md is that report, including the three this work
introduced itself and the one that turned out to be caused by an instruction to
hard-reload after each deployment.

Node suite 1209 passed, hub suite 866 passed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HCGdheDLxGReuKHga3BtST

1 files changed, 38 insertions, 0 deletions

diff --git a/packages/meshbay-hub/tests/test_upload_seal_client.py b/packages/meshbay-hub/tests/test_upload_seal_client.py
index d6f9156..2e4bfb5 100644
--- a/packages/meshbay-hub/tests/test_upload_seal_client.py
+++ b/packages/meshbay-hub/tests/test_upload_seal_client.py
@@ -167,3 +167,41 @@ def test_the_client_refuses_an_older_node_before_sending_a_chunk(_gek):
     assert result["state"] == "rejected"
     assert "older MeshBay" in result["message"]
     assert result["frames"] == [], "a chunk was sent to a node that cannot open it"
+
+
+def test_an_interrupted_upload_resumes_where_the_node_stopped(tmp_path, _gek):
+    """
+    The browser asks, the node answers, and the second attempt sends only what
+    is missing.
+
+    Both halves are the shipped ones: the frames come from the real
+    `uploadFile`, the answer comes from the real node handler. What is asserted
+    is the thing that used to be impossible — an upload interrupted at chunk two
+    of five that sends three chunks instead of five.
+    """
+    body = bytes(range(256)) * ((CHUNK * 5) // 256 + 1)
+    body = body[:CHUNK * 5]
+    first = _run_probe(_probe_input(_gek, "send",
+                                    file={"name": "film.mkv", "data": body.hex()}))
+    frames = [msgpack.unpackb(bytes.fromhex(f), raw=False)
+              for f in first["frames"]]
+    assert [f["chunk_index"] for f in frames] == [-1, 0, 1, 2, 3, 4]
+
+    # The link drops after two chunks.
+    session = _node_session(tmp_path, _gek)
+    for frame in frames[1:3]:
+        session._do_file_upload(frame)
+    assert not [m for m in session.sent if m.get("type") == "error"]
+
+    # It comes back and asks.
+    session.sent.clear()
+    session._do_file_upload(frames[0])
+    probe_ack = msgpack.packb(session.sent[-1], use_bin_type=True).hex()
+
+    second = _run_probe(_probe_input(
+        _gek, "send", file={"name": "film.mkv", "data": body.hex()},
+        probe_ack=probe_ack))
+    resumed = [msgpack.unpackb(bytes.fromhex(f), raw=False)["chunk_index"]
+               for f in second["frames"]]
+    assert resumed == [-1, 2, 3, 4], (
+        f"sent {resumed} — the answer to the probe was not used")