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, 67 insertions, 44 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/node-page.js b/packages/meshbay-hub/src/meshbay_hub/static/node-page.js
index 2a0b0d7..ec73128 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/node-page.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/node-page.js
@@ -47,21 +47,35 @@ function NodeServicePanel({ onChanged }) {
     }
   }, [refresh, onChanged]);
 
-  const toggleAutostart = useCallback(() => {
-    act('autostart', () => (info && info.autostart
-      ? platform.node.autostart.remove()
-      : platform.node.autostart.install()));
-  }, [act, info]);
+  // "off" / "signin" / "service" -- derived from the status payload, no new
+  // backend field needed: mode/autostart already distinguish all three.
+  const startupMode = (i) => {
+    if (!i) return 'off';
+    if (i.mode === 'service') return i.mode;
+    return i.autostart ? 'signin' : 'off';
+  };
 
   // Switching mode itself — the installer's own choice is effectively one-shot
   // (it skips the question once the firewall rules exist for any reason, and
   // per-user mode sets those up on its own with no Scheduled Task), so this is
   // the only way back in if service mode was declined, or out if it is no
   // longer wanted. One elevation, task + firewall together, same script.
-  const toggleServiceMode = useCallback(() => {
-    act('serviceMode', () => (info && info.mode === 'service'
-      ? platform.node.serviceMode.remove()
-      : platform.node.serviceMode.install()));
+  //
+  // The two mechanisms are mutually exclusive by construction here: never
+  // both installed at once, which would start the daemon twice (once at
+  // boot via the Scheduled Task, again at sign-in via the Startup .vbs).
+  // Always remove whichever one is currently active before installing the
+  // target, so every transition -- not just the two that used to be
+  // separate toggles -- keeps that invariant.
+  const changeStartupMode = useCallback((target) => {
+    const current = startupMode(info);
+    if (target === current) return;
+    act('startupMode', async () => {
+      if (current === 'service') await platform.node.serviceMode.remove();
+      else if (current === 'signin') await platform.node.autostart.remove();
+      if (target === 'service') await platform.node.serviceMode.install();
+      else if (target === 'signin') await platform.node.autostart.install();
+    });
   }, [act, info]);
 
   if (!platform.node.service.available) return null;
@@ -79,44 +93,53 @@ function NodeServicePanel({ onChanged }) {
   const label = info.installed ? t('node.service_state_' + stateKey)
                                 : t('node.service_not_installed');
 
+  // Own row, below the status/actions card rather than a further item
+  // crammed into its flex-wrap line -- that (plus two independent toggles
+  // for what is really one choice) is what made this a mess before.
+  const showStartupRow = (platform.node.autostart.available
+    || platform.node.serviceMode.available) && typeof info.mode === 'string';
+
   return html`
-    <div class="node-service">
-      <div class="node-service-status">
-        <span class="presence presence-${dot}" title="${label}" aria-label="${label}"></span>
-        <span>${label}</span>
-      </div>
-      ${err && html`<div class="error-msg">${err}</div>`}
-      <div class="node-service-actions">
-        <button class="btn btn-small btn-secondary" disabled=${!!busy || running}
-          onClick=${() => act('start', () => platform.node.start())}>
-          ${busy === 'start' ? t('node.service_starting') : t('node.service_start')}</button>
-        ${info.installed && html`
-          <button class="btn btn-small btn-secondary" disabled=${!!busy || !running}
-            onClick=${() => act('stop', () => platform.node.service.stop())}>
-            ${busy === 'stop' ? t('node.service_stopping') : t('node.service_stop')}</button>
-          <button class="btn btn-small btn-secondary" disabled=${!!busy}
-            onClick=${() => act('restart', () => platform.node.service.restart())}>
-            ${busy === 'restart' ? t('node.service_restarting') : t('node.service_restart')}</button>
+    <div>
+      <div class="node-service">
+        <div class="node-service-status">
+          <span class="presence presence-${dot}" title="${label}" aria-label="${label}"></span>
+          <span>${label}</span>
+        </div>
+        ${err && html`<div class="error-msg">${err}</div>`}
+        <div class="node-service-actions">
+          <button class="btn btn-small btn-secondary" disabled=${!!busy || running}
+            onClick=${() => act('start', () => platform.node.start())}>
+            ${busy === 'start' ? t('node.service_starting') : t('node.service_start')}</button>
+          ${info.installed && html`
+            <button class="btn btn-small btn-secondary" disabled=${!!busy || !running}
+              onClick=${() => act('stop', () => platform.node.service.stop())}>
+              ${busy === 'stop' ? t('node.service_stopping') : t('node.service_stop')}</button>
+            <button class="btn btn-small btn-secondary" disabled=${!!busy}
+              onClick=${() => act('restart', () => platform.node.service.restart())}>
+              ${busy === 'restart' ? t('node.service_restarting') : t('node.service_restart')}</button>
+          `}
+        </div>
+        ${info.mode === 'service' && html`
+          <p class="node-hint">${t('node.service_mode_hint')}</p>
         `}
       </div>
-      ${info.mode === 'service' && html`
-        <p class="node-hint">${t('node.service_mode_hint')}</p>
-      `}
-      ${platform.node.autostart.available && typeof info.autostart === 'boolean' && html`
-        <label class="toggle-switch ${busy ? 'toggle-switch-disabled' : ''}">
-          <input type="checkbox" checked=${info.autostart} disabled=${!!busy}
-            onChange=${toggleAutostart} />
-          <span class="toggle-switch-track"><span class="toggle-switch-thumb"></span></span>
-          ${' '}${busy === 'autostart' ? t('node.autostart_updating') : t('node.autostart_label')}
-        </label>
-      `}
-      ${platform.node.serviceMode.available && typeof info.mode === 'string' && html`
-        <label class="toggle-switch ${busy ? 'toggle-switch-disabled' : ''}">
-          <input type="checkbox" checked=${info.mode === 'service'} disabled=${!!busy}
-            onChange=${toggleServiceMode} />
-          <span class="toggle-switch-track"><span class="toggle-switch-thumb"></span></span>
-          ${' '}${busy === 'serviceMode' ? t('node.service_mode_updating') : t('node.service_mode_label')}
-        </label>
+      ${showStartupRow && html`
+        <div class="settings-row">
+          <span class="settings-label">${t('node.startup_mode_label')}</span>
+          <select class="settings-select" disabled=${!!busy}
+            value=${startupMode(info)}
+            onChange=${(e) => changeStartupMode(e.target.value)}>
+            <option value="off">${t('node.startup_mode_off')}</option>
+            <option value="signin">${t('node.startup_mode_signin')}</option>
+            <option value="service" disabled=${!info.canElevate}>
+              ${t('node.startup_mode_service')}</option>
+          </select>
+        </div>
+        ${busy === 'startupMode' && html`
+          <p class="settings-hint">${t('node.startup_mode_updating')}</p>`}
+        ${!info.canElevate && html`
+          <p class="settings-hint">${t('node.startup_mode_service_unavailable_hint')}</p>`}
       `}
     </div>`;
 }