revert(winstate): drop the parked restored-size rect, it left a stub window

Widening rcNormalPosition while the window was down did remove the restore
flash, but SetWindowPlacement left a small stub frame in a corner of the screen
whenever the window was maximised — during the minimise animation and equally
once the window was already iconic. A permanent visible artefact is worse than
an ugly animation, so this goes back to the validated behaviour: correct final
state, flash still present.

The flash itself is an FMX bug, reproducible in an empty FMX app. Rationale and
the five rejected approaches are recorded in TEST_SCENARIOS.md I1.

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

delphi-backend/UMainForm.pas

@@ -19,7 +19,7 @@ uses
   System.SysUtils, System.Classes, System.UITypes, System.NetEncoding,
   System.StrUtils, System.Generics.Collections, System.IOUtils, System.JSON,
   System.Net.HttpClient, System.Net.URLClient,
-  Winapi.Windows, Winapi.ShellAPI, Winapi.MultiMon,
+  Winapi.Windows, Winapi.ShellAPI,
   FMX.Forms, FMX.Controls, FMX.Controls.Presentation, FMX.StdCtrls,
   FMX.Memo, FMX.Memo.Types, FMX.ScrollBox, FMX.Edit, FMX.Layouts, FMX.Types,
   FMX.Dialogs, FMX.DialogService,
@@ -87,13 +87,6 @@ type
     // True from "minimise starts" until just after the restore settles, so the
     // resizes FMX fires while restoring are not recorded as user intent.
     FIgnoreResizes: Boolean;
-    // Re-entrance guard: ApplyWantedWindowState runs from OnResize and its own
-    // ShowWindow fires another OnResize.
-    FApplyingWindowState: Boolean;
-    // The window's real restored-size rectangle, parked while we temporarily
-    // widen it to the monitor's work area (see WinStateMinimizeStart).
-    FSavedNormalRect: TRect;
-    FNormalRectHijacked: Boolean;
     // Set from activate until the queued correction runs, so the restore's
     // own resize is not mistaken for the user resizing the window.
     FRestoring: Boolean;
@@ -184,7 +177,6 @@ type
     procedure WinStateMinimizeStart;
     procedure WinStateMinimizeEnd;
     procedure ApplyWantedWindowState;
-    procedure ReleaseNormalRect;
   end;
 
 var
@@ -1661,70 +1653,21 @@ end;
 
 // The window is going down: from here until the restore settles, every resize
 // FMX fires is part of that transition, never a user gesture.
-// FMX loses the maximised state whenever Windows minimises the form from the
-// outside — reproducible in an empty FMX app, so there is nothing to fix on our
-// side of it. The window comes back at its RESTORED size and DWM animates the
-// frame growing towards that rectangle, which is the flash; every correction we
-// can run (OnResize, MINIMIZEEND) lands after that decision is made.
-//
-// So instead of fighting the restore, make the rectangle it restores to
-// harmless: park the real one and widen it to the monitor's work area while the
-// window is down. FMX still restores "to normal", except normal is now
-// full-screen — nothing visibly grows — and the OnResize correction promotes it
-// to a true maximised window right after. ApplyWantedWindowState puts the real
-// rectangle back, so un-maximising later still lands on the user's own size.
 procedure TMainForm.WinStateMinimizeStart;
-var
-  LHwnd: HWND;
-  LPlace: TWindowPlacement;
-  LMonitor: TMonitorInfo;
 begin
   FIgnoreResizes := True;
-  if FNormalRectHijacked or (not FWantMaximized) then Exit;
-  LHwnd := WindowHandleToPlatform(Self.Handle).Wnd;
-  if LHwnd = 0 then Exit;
-  LPlace := Default(TWindowPlacement);
-  LPlace.length := SizeOf(LPlace);
-  if not GetWindowPlacement(LHwnd, @LPlace) then Exit;
-  LMonitor := Default(TMonitorInfo);
-  LMonitor.cbSize := SizeOf(LMonitor);
-  if not GetMonitorInfo(MonitorFromWindow(LHwnd, MONITOR_DEFAULTTONEAREST), @LMonitor) then Exit;
-  FSavedNormalRect := LPlace.rcNormalPosition;
-  FNormalRectHijacked := True;
-  LPlace.rcNormalPosition := LMonitor.rcWork;
-  // The window is maximised right now, so touching only rcNormalPosition moves
-  // nothing on screen.
-  SetWindowPlacement(LHwnd, @LPlace);
-end;
-
-// Undo the hijack above. Safe to call whenever: it is a no-op unless the real
-// rectangle is currently parked.
-procedure TMainForm.ReleaseNormalRect;
-var
-  LHwnd: HWND;
-  LPlace: TWindowPlacement;
-begin
-  if not FNormalRectHijacked then Exit;
-  FNormalRectHijacked := False;
-  LHwnd := WindowHandleToPlatform(Self.Handle).Wnd;
-  if LHwnd = 0 then Exit;
-  LPlace := Default(TWindowPlacement);
-  LPlace.length := SizeOf(LPlace);
-  if not GetWindowPlacement(LHwnd, @LPlace) then Exit;
-  LPlace.rcNormalPosition := FSavedNormalRect;
-  SetWindowPlacement(LHwnd, @LPlace);
 end;
 
 // Back up: re-apply what the user had.
 procedure TMainForm.WinStateMinimizeEnd;
 begin
-  // Normally a no-op by now: the correction already ran from the restore's own
-  // OnResize, which Windows delivers BEFORE this hook. Kept for the paths that
-  // reach here without a resize.
+  // Inline, not queued: by the time this hook fires Windows has already put the
+  // window back at its normal size, and measurement showed nothing touches the
+  // state afterwards — the extra message-loop turn a ForceQueue costs was the
+  // whole flicker, one painted normal-sized frame before the correction landed.
   ApplyWantedWindowState;
-  // Net: whatever path we took, the real restored-size rectangle must never
-  // stay parked past the end of a restore.
-  ReleaseNormalRect;
+  // Second pass anyway, in case FMX sizes the window after us on some path.
+  // Idempotent: it only acts when the state still disagrees.
   TThread.ForceQueue(nil,
     procedure
     begin
@@ -1734,35 +1677,21 @@ begin
     end);
 end;
 
-// Re-entrant by nature: it is called from OnResize and its own ShowWindow fires
-// another OnResize. FApplyingWindowState keeps that one pass deep.
 procedure TMainForm.ApplyWantedWindowState;
 var
   LHwnd: HWND;
 begin
-  if FApplyingWindowState then Exit;
   LHwnd := WindowHandleToPlatform(Self.Handle).Wnd;
-  // Iconic means the window is genuinely down (minimise-to-tray, autofill):
-  // nothing to correct, and forcing a state here would fight the hide.
   if (LHwnd = 0) or IsIconic(LHwnd) then Exit;
-  if FWantMaximized = IsZoomed(LHwnd) then Exit;
-  FApplyingWindowState := True;
-  try
-    if FWantMaximized then
-    begin
-      LogLine('[winstate] re-maximising after restore');
-      ShowWindow(LHwnd, SW_SHOWMAXIMIZED);
-      // Maximised again, so writing rcNormalPosition back is invisible here —
-      // and it has to happen before the user can un-maximise.
-      ReleaseNormalRect;
-    end
-    else
-    begin
-      LogLine('[winstate] restoring to normal after restore');
-      ShowWindow(LHwnd, SW_RESTORE);
-    end;
-  finally
-    FApplyingWindowState := False;
+  if FWantMaximized and (not IsZoomed(LHwnd)) then
+  begin
+    LogLine('[winstate] re-maximising after restore');
+    ShowWindow(LHwnd, SW_SHOWMAXIMIZED);
+  end
+  else if (not FWantMaximized) and IsZoomed(LHwnd) then
+  begin
+    LogLine('[winstate] restoring to normal after restore');
+    ShowWindow(LHwnd, SW_RESTORE);
   end;
 end;
 
@@ -1772,15 +1701,7 @@ procedure TMainForm.FormResizeTrackState(Sender: TObject);
 var
   LHwnd: HWND;
 begin
-  // A minimise / restore is in flight, so this resize is never a user gesture —
-  // but it IS where Windows applies the normal-sized restore, one message before
-  // MINIMIZEEND is delivered. Correcting from the hook therefore always paints a
-  // normal frame first; this is the earliest point we get.
-  if FIgnoreResizes then
-  begin
-    ApplyWantedWindowState;
-    Exit;
-  end;
+  if FIgnoreResizes then Exit;
   LHwnd := WindowHandleToPlatform(Self.Handle).Wnd;
   if (LHwnd = 0) or IsIconic(LHwnd) then Exit;
   if FWantMaximized <> IsZoomed(LHwnd) then