fix(cli): make the command-line client work on Windows

Its suite had only run on Linux. On Windows, against a real hub and node and
from the installed meshbay-cli.exe:

- secrets.enc was written in text mode (os.open without O_BINARY): every 0x0A
  of the ciphertext became CR LF and the saved session "does not open with
  its key" on the next run.
- isatty() is true for NUL, so a script run with `< NUL` or by the Task
  Scheduler was asked questions instead of told to pass --yes;
  output.terminal() checks for a real console.
- Ctrl+C waited for the selector loop's next timer, up to half a minute in
  `chat --follow`; the loop now points the signal wakeup at its self-pipe,
  as the proactor does.
- Right-click copy and paste raised: asyncio cannot start a process on the
  selector loop; the clipboard tool runs in a thread.
- Tab completion of remote paths ran on the default (proactor) loop, which
  never opens a node, and wrote in the locale encoding; the PowerShell script
  now reads it as UTF-8.
- `get -R` into a folder past MAX_PATH died with a traceback; get, put, the
  resume file and the interactive mode use the extended form at each disk
  call, as the node does.
- `groups` showed a SQLite hub's naive UTC time as local time.

The opt-in end-to-end suite now runs on Windows (16 tests: Chrome found under
Program Files and started with the real environment, VLC as the player, Ctrl+C
through a console of its own, PowerShell 5.1 completion of an accented name).

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

3 files changed, 37 insertions, 10 deletions

diff --git a/packages/meshbay-cli/src/meshbay_cli/client/store.py b/packages/meshbay-cli/src/meshbay_cli/client/store.py
index c48fe89..00ff9f3 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/store.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/store.py
@@ -63,7 +63,10 @@ def data_dir() -> Path:
 def _write_private(path: Path, data: bytes) -> None:
     """Atomically, readable by this user only."""
     tmp = path.with_name(path.name + ".tmp")
-    fd = os.open(tmp, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
+    # O_BINARY: without it Windows opens in text mode and writes every 0x0A of
+    # the ciphertext as CR LF, and the secrets no longer open.
+    flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC | getattr(os, "O_BINARY", 0)
+    fd = os.open(tmp, flags, 0o600)
     try:
         os.write(fd, data)
         os.fsync(fd)
diff --git a/packages/meshbay-cli/src/meshbay_cli/client/transfers.py b/packages/meshbay-cli/src/meshbay_cli/client/transfers.py
index 2cbf4cd..177c78b 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/transfers.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/transfers.py
@@ -128,7 +128,8 @@ class Resume:
         sidecar = target.with_name(target.name + PART_SUFFIX + ".json")
         done = 0
         try:
-            meta = json.loads(sidecar.read_text(encoding="utf-8"))
+            with open(long_path(sidecar), encoding="utf-8") as f:
+                meta = json.load(f)
             if meta.get("id") == entry["id"] and meta.get("size") == entry["size"]:
                 # Every chunk but the last is whole, so the complete ones are
                 # what the part's length says.
@@ -198,8 +199,8 @@ def _prepare_part(resume: Resume, entry: dict, start: int) -> None:
             pass
     else:
         os.truncate(part, start * DOWNLOAD_CHUNK)
-    resume.sidecar.write_text(json.dumps({"id": entry["id"], "size": entry["size"]}),
-                              encoding="utf-8")
+    with open(long_path(resume.sidecar), "w", encoding="utf-8") as f:
+        json.dump({"id": entry["id"], "size": entry["size"]}, f)
 
 
 def _publish(resume: Resume, target: Path, overwrite: bool) -> None:
@@ -220,7 +221,7 @@ def _publish(resume: Resume, target: Path, overwrite: bool) -> None:
                 raise TransferError(f"{target} already exists.") from None
             os.replace(part, dest)
     with contextlib.suppress(OSError):
-        resume.sidecar.unlink()
+        os.unlink(long_path(resume.sidecar))
     if sys.platform == "win32":
         mark_of_the_web(target)
 
diff --git a/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py b/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py
index 070e686..b4ec781 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/upload_plan.py
@@ -12,7 +12,7 @@ import stat
 from dataclasses import dataclass
 from pathlib import Path
 
-from meshbay_common.paths import fold
+from meshbay_common.paths import fold, long_path
 
 from ..errors import USAGE, CliError
 from ..output import safe
@@ -36,7 +36,7 @@ def plan_upload(sources: list[str], recursive: bool):
     for src in sources:
         path = Path(src).expanduser()
         try:
-            st = path.stat()
+            st = os.stat(long_path(path))
         except OSError as e:
             problems.append(f"{src}: {e.strerror}")
             continue
@@ -51,18 +51,18 @@ def plan_upload(sources: list[str], recursive: bool):
         elif stat.S_ISDIR(st.st_mode):
             if not recursive:
                 raise CliError(USAGE, f"{safe(src)} is a folder; use -R.")
-            for here, subdirs, names in os.walk(path):
+            for here, subdirs, names in _walk(path):
                 rel = [top] + list(Path(here).relative_to(path).parts)
                 dirs.append(rel)
                 for d in list(subdirs):
-                    if (Path(here) / d).is_symlink():
+                    if os.path.islink(long_path(Path(here) / d)):
                         subdirs.remove(d)
                         problems.append(f"{Path(here) / d} is a link to a folder; not "
                                         "followed")
                 for n in names:
                     p = Path(here) / n
                     try:
-                        st_n = p.stat()
+                        st_n = os.stat(long_path(p))
                     except OSError as e:
                         problems.append(f"{p}: {e.strerror}")
                         continue
@@ -74,6 +74,29 @@ def plan_upload(sources: list[str], recursive: bool):
     return dirs, files, problems
 
 
+def _walk(top: Path):
+    """`os.walk` for a tree that may go past Windows' MAX_PATH: each folder is
+    listed under its long form (`long_path`, which only prefixes a long path, so
+    a short top alone would not do) and the paths given back stay plain."""
+    stack = [top]
+    while stack:
+        here = stack.pop()
+        try:
+            with os.scandir(long_path(here)) as it:
+                entries = list(it)
+        except OSError:
+            continue
+        subdirs, names = [], []
+        for e in entries:
+            try:
+                is_dir = e.is_dir()
+            except OSError:
+                is_dir = False
+            (subdirs if is_dir else names).append(e.name)
+        yield here, subdirs, names          # the caller prunes and orders subdirs
+        stack.extend(here / d for d in reversed(subdirs))
+
+
 def taken_names(tree: Tree, folder: str, names: list[str]) -> set[str]:
     """The names among `names` already in `folder`, compared without case."""
     there = [i.name for i in tree.children(folder, include_unavailable=True)]