fix(startup): hide the taskbar proxy too, and trace the --tray timeline

The window still showed, taskbar entry included. Two things.

The taskbar button belongs to the FMX proxy window (TFMAppClass), a separate
top-level window from the form — hiding the form alone never removed it.
FindFMXAppWindow moves from private to public so the activate-hide can drop
both. (Guarded on Assigned(FBridge): the handler is installed at line 222,
the bridge is created at 268.)

And rather than guess a fourth time at FMX's startup order — the same trap as
the window-state saga, which only fell to instrumentation — this logs a
millisecond timeline: FormCreate begin/end, the activate-hide, and the
deferred MinimizeToTray. Whichever gap holds the second will be obvious.

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

delphi-backend/Source/PM.Bridge.pas

@@ -140,8 +140,11 @@ type
     procedure PrepareNid;
     procedure ShowTrayMenu;
     procedure ShowFirstTimeBalloon;
-    function FindFMXAppWindow: HWND;
   public
+    // The FMX taskbar proxy (TFMAppClass) — a SEPARATE top-level window from
+    // the form, and the one that owns the taskbar entry. Public so the host
+    // can hide it during a --tray launch, before MinimizeToTray gets to run.
+    function FindFMXAppWindow: HWND;
     // Tray balloon (caller applies its own gating setting). Used for
     // messages the user must see while the window is hidden — e.g. an
     // autofill blocked by an elevated target.