fix(startup): start the proxy watcher from the .dpr, before the form exists

Decisive observation: the taskbar button is already up before FormCreate is
entered. Everything I had tried lived inside the form, so all of it ran after
the button was drawn — the watcher included, which is why moving it around
never helped.

StartTrayProxyHider is now exported from UMainForm and called from the .dpr
right after Application.Initialize, before CreateForm. It polls every 5 ms and
hides our TFMAppClass proxy unconditionally (the button can be up before
WS_VISIBLE reads as set, which the previous IsWindowVisible check would have
skipped), stopping as soon as the tray startup completes so a user restoring
from the tray is never fought.

Raw Win32 only — FindWindowEx + ShowWindow, no FMX object touched at that
point, which is what made the earlier .dpr attempt crash.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

delphi-backend/PMServer.dpr

@@ -1,6 +1,7 @@
 program PMServer;
 
 uses
+  System.SysUtils,          // FindCmdLineSwitch
   System.StartUpCopy,
   FMX.Forms,
   PM.SingleInstance in 'Source\PM.SingleInstance.pas',
@@ -43,6 +44,13 @@ begin
     Exit;
 
   Application.Initialize;
+  // --tray ("Start with Windows"): FMX puts its taskbar proxy on screen before
+  // FormCreate is ever reached — measured — so the watcher has to start here,
+  // before the form is built. It only touches raw Win32 (FindWindowEx +
+  // ShowWindow), never an FMX object: an earlier attempt that poked
+  // MainForm.Visible/Handle at this point died with an access violation.
+  if FindCmdLineSwitch('tray', True) then
+    StartTrayProxyHider;
   Application.CreateForm(TMainForm, MainForm);
   Application.Run;
 end.