fix: set the Windows node up at sign-in, and stop it for real

Found by the first Windows beta tester, then reproduced on a clean install.

After a service-mode install nothing set the node up for the account that
signed in: the boot task started a node that quit ("hub.username not set"),
and the sidebar showed Node / Create group only once the hub held a node key.
The only way to the wizard that provisions was the home page's welcome card,
which an account already in a group never sees. The way out was
`meshbay-node init` and the key pasted on the profile page -- which is also
what PACKAGING-GUIDE.md told people to do.

- main.js `node:ensure`, called by app.js at sign-in: provisions, starts and
  links the node this build ships (Windows, bundled node only). A node set up
  for another account, or an account linked to another node, is left alone.
  node:start waits for it, so the two never race.
- The sidebar shows the Node section when a node exists on this machine.
- The Node page's status is the node's: its control API and the process
  list, not the service task's state (a node started from a terminal ran
  while the page said Stopped). Stop says Stopped only once no
  meshbay-node.exe is left, and stays offered for a process that answers
  nothing.
- CLI stop kills the pid that answered when a graceful stop does not finish,
  and fails with the reason when a node process is still there.
- The daemon ends its process 3s after _shutdown(): Python's exit waited for a
  busy indexer thread, with the control API already closed. Armed by main()
  only, never by a daemon run inside a test.
- node.toml is read as utf-8-sig (PowerShell 5.1 writes a BOM), and a config
  that cannot be read is logged instead of dying silently in service mode.
- "Pair this browser" queues the code for the next group of this node to
  open instead of saying "Paired successfully"; no banner before a group.
- test_e2e_windows_app.py (opt-in, MESHBAY_WIN_E2E=1) drives the installed
  app against a throwaway hub: fresh account to linked node, Stop, Start,
  Restart, checked against the real processes.

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

1 files changed, 29 insertions, 0 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/platform.py b/packages/meshbay-node/src/meshbay_node/platform.py
index 88db83d..c0e4d00 100644
--- a/packages/meshbay-node/src/meshbay_node/platform.py
+++ b/packages/meshbay-node/src/meshbay_node/platform.py
@@ -397,6 +397,35 @@ def autostart_end() -> None:
     subprocess.run(argv, capture_output=True)
 
 
+def node_pids() -> list[int]:
+    """Every meshbay-node.exe running, in any session, except this process and
+    its parent (the CLI is meshbay-node.exe too). Empty off Windows.
+
+    What says whether a node is still there after a stop: its control API
+    closes first, so a process that has not exited yet answers nothing and
+    used to count as gone.
+    """
+    if sys.platform != "win32":
+        return []
+    r = subprocess.run(["tasklist", "/FI", f"IMAGENAME eq {NODE_IMAGE}", "/NH", "/FO", "CSV"],
+                       capture_output=True, text=True)
+    mine = {os.getpid(), os.getppid()}
+    pids = []
+    for line in r.stdout.splitlines():
+        cells = [c.strip('"') for c in line.split('","')]
+        if len(cells) > 1 and cells[1].isdigit() and int(cells[1]) not in mine:
+            pids.append(int(cells[1]))
+    return pids
+
+
+def kill_pid(pid: int) -> None:
+    """Force-stop one process and its children (its ffmpeg transcodes). Reaches
+    this session only, unless the caller is elevated. Windows only: systemd
+    stops the node everywhere else."""
+    if sys.platform == "win32":
+        subprocess.run(["taskkill", "/F", "/T", "/PID", str(pid)], capture_output=True)
+
+
 # ── Service mode (Windows, opt-in at install time) ───────────────────────────
 #
 # The Startup-folder .vbs above only ever runs after *this* user signs in. A