feat(autostart): "Start with Windows" toggle

- PM.AutoStart wraps HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
  Value "PMServer" = "<exe>" -tray. Per-user, no admin required, shows
  up in Task Manager → Startup so the user can override from there.

- UMainForm honours the -tray CLI flag (set by the registry entry):
  after the server starts, MinimizeToTray via TThread.ForceQueue so the
  app comes up directly in the tray with no visible window flash.

- Bridge cmd://autostart/{get,set} + Bridge.getAutoStart() /
  setAutoStart() / onAutoStartStatus(). Settings exposes a toggle in
  the Security section, visible only when Bridge.active (the PHP
  frontend can't touch the registry).

- Toggle reads "on" only when the registered command matches the
  current exe path, so a stale entry from a moved exe lets the user
  re-enable to refresh.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

index.html

@@ -396,6 +396,20 @@
                         <span class="toggle-slider"></span>
                     </label>
                 </div>
+                <div class="setting-row" id="settingAutoStartRow">
+                    <span>
+                        Start with Windows
+                        <small class="setting-hint">
+                            Launch this app in the tray when you sign in to
+                            Windows — so the autofill hotkeys are ready
+                            immediately. Device-only setting (per Windows user).
+                        </small>
+                    </span>
+                    <label class="toggle">
+                        <input type="checkbox" id="settingAutoStart">
+                        <span class="toggle-slider"></span>
+                    </label>
+                </div>
                 <div class="setting-row" id="settingAutofillRow">
                     <span>
                         Autofill with global hotkey