fix(win): graceful shutdown, one startup-mode control, and a stray-\r bug

Windows-only changes, all found by actually running the previous session's
work rather than by review alone:

- CTRL_CLOSE_EVENT/LOGOFF/SHUTDOWN handler (platform.py, ctypes
  SetConsoleCtrlHandler) so closing a console window, signing off, or a
  system shutdown runs the daemon's real _shutdown() instead of Windows
  just ending the process — closing WebRTC sessions and any in-flight
  ffmpeg transcode instead of orphaning it. `taskkill /F` itself stays
  uncatchable (like SIGKILL), so autostart_run() now spawns with
  CREATE_NEW_PROCESS_GROUP instead of DETACHED_PROCESS and autostart_end()
  tries CTRL_BREAK_EVENT against the recorded pid first, falling back to
  the hard kill only if that doesn't stop it in time.

- Replaced the Node page's two independent autostart/service-mode toggles
  with one "start automatically" select (off / at sign-in / as a
  background service). The old pair let both be active at once — starting
  the daemon twice, at boot and at sign-in — and their layout broke
  wrapping inside .node-service's flex row. The new control always removes
  whichever mechanism is active before installing the target; platform.py's
  service_install() does the same on the CLI side. The "background
  service" option disables itself (with a hint pointing at the CLI) when
  running unpackaged, since service-mode.ps1/service.ps1/firewall.ps1 all
  assume an installed build's layout — verified live rather than assumed
  by actually running those scripts unelevated.

- findNodeBinary() no longer bakes a stray \r into resolved paths. Found by
  rebooting after enabling per-user autostart: where.exe listed two
  matches, and stdout.trim().split('\n')[0] only strips the whole string's
  ends, leaving line one's own trailing \r attached — which landed inside
  the Startup .vbs's quoted path and broke it with "Unterminated string
  constant" at boot. Fixed by splitting on \r?\n and trimming every line.

- Dependency audit for the Windows installer (docs/WINDOWS-PORT.md): no
  VC++ Redistributable needed, confirmed by inspecting the built
  node-runtime's actual import table rather than assuming. New
  docs/windows-build.md: a concise clone-to-installer build guide.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/packages/meshbay-node/tests/test_packaging_win.py b/packages/meshbay-node/tests/test_packaging_win.py
index 21aaf29..0cf6367 100644
--- a/packages/meshbay-node/tests/test_packaging_win.py
+++ b/packages/meshbay-node/tests/test_packaging_win.py
@@ -71,6 +71,25 @@ def test_the_node_runtime_is_carried_as_an_extraresource():
         "extraResources puts it")
 
 
+def test_find_node_binary_strips_stray_cr_from_multiline_where_output():
+    """
+    where.exe/which can list more than one match on PATH, and each line
+    keeps its own trailing \\r on Windows. `stdout.trim().split('\\n')[0]`
+    only strips the ends of the *whole* string, so with 2+ matches a stray
+    \\r stayed glued to the end of the first line -- which then landed
+    inside the quoted path written into the Startup .vbs and broke
+    VBScript's parser with "Unterminated string constant" the next time
+    Windows ran it at sign-in. Reproduced live 2026-09-05 (this user's own
+    machine has both a dev venv and an installed build on PATH) and fixed
+    by splitting on \\r?\\n and trimming each candidate line individually.
+    """
+    main_js = (CLIENT / "src" / "main.js").read_text(encoding="utf-8")
+    assert "stdout.split(/\\r?\\n/)" in main_js, (
+        "findNodeBinary must split where.exe/which output on \\r?\\n and "
+        "trim each line, not a single stdout.trim() over the whole blob")
+    assert "stdout.trim().split('\\n')[0]" not in main_js
+
+
 def test_firewall_helper_is_carried_as_an_extraresource():
     """packaging/win/firewall.ps1 must ride into resources/, at the fixed
     path installer.nsh invokes it from ($INSTDIR\\resources\\firewall.ps1)."""