fix(node): index, serve and write files past Windows' MAX_PATHHEADmain

With the system's default setting (LongPathsEnabled off) every call given
a plain path of 260 characters or more refuses it, so a deep library was
partly invisible: the walk could not list such a directory and its files
never reached the members.

The node now hands each call that touches a group's disk the extended
form (paths.long_path), and keeps the plain path in the index, the hash
cache and the log. A directory is listed under its long form and its
entries named from the plain one (indexer.walk_files, wire._walk_dirs).
Covered: the walk, stats and hashing, reconcile and the watcher, the
folder list members see, serving over WebRTC and QUIC, deletion, uploads
and their recovery, folder creation and removal, audio tags and the
cover beside a track, photos, and a show's episode numbering. ffmpeg
extends a long path itself and keeps the plain one.

long_path now normalises before prefixing (the extended form skips the
system's normalisation) and starts at 248 characters, where creating a
directory is already refused.

test_long_paths.py runs with the setting off: 15 of its 17 tests fail
without the change. Checked by hand in the installed app with files at
312 to 380 characters.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/transport/quic_server.py b/packages/meshbay-node/src/meshbay_node/transport/quic_server.py
index 715448f..3974a2f 100644
--- a/packages/meshbay-node/src/meshbay_node/transport/quic_server.py
+++ b/packages/meshbay-node/src/meshbay_node/transport/quic_server.py
@@ -48,6 +48,7 @@ from meshbay_common.handshake import (
     quic_binding,
     verify_proof,
 )
+from meshbay_common.paths import long_path
 from meshbay_common.protocol import MNP, file_chunk_wire
 
 from meshbay_node.indexer import GroupIndex
@@ -434,7 +435,7 @@ class _MNPServerProtocol(QuicConnectionProtocol):
         if file_path is None:
             self._send(stream_id, {"type": "error", "detail": ROOT_NOT_SERVED})
             return
-        if not file_path.exists():
+        if not os.path.exists(long_path(file_path)):
             self._send(stream_id, {"type": "error", "detail": "File not on disk"})
             return
 
@@ -463,7 +464,7 @@ def _read_and_encrypt(
     file_id: str = "",
 ) -> dict:
     """Read one chunk off disk and encrypt it, in the one shape every transport uses."""
-    with open(file_path, "rb") as f:
+    with open(long_path(file_path), "rb") as f:
         f.seek(chunk_index * CHUNK_SIZE)
         plaintext = f.read(CHUNK_SIZE)
     return file_chunk_wire(gek, plaintext, chunk_index, file_hash, file_id)