gpui: Fix show: false support on Windows to create an invisible window (#18161)

Release Notes:

- N/A
- 
The `show` of WindowOptions is valid on macOS but not on Windows, this
changes to fix it to support create an invisible window.

```bash
cargo run -p gpui --example window
```

## Before



https://github.com/user-attachments/assets/4157bdaa-39a7-44df-bbdc-30b00e9c61e9


## After



https://github.com/user-attachments/assets/d48fa524-0caa-4f87-932d-01d7a468c488


https://github.com/user-attachments/assets/dd052f15-c8db-4a2a-a6af-a7c0ffecca84

crates/gpui/src/platform/mac/window.rs

@@ -707,7 +707,7 @@ impl MacWindow {
                 }
             }
 
-            if focus {
+            if focus && show {
                 native_window.makeKeyAndOrderFront_(nil);
             } else if show {
                 native_window.orderFront_(nil);

crates/gpui/src/platform/windows/window.rs

@@ -287,7 +287,7 @@ impl WindowsWindow {
                 .map(|title| title.as_ref())
                 .unwrap_or(""),
         );
-        let (dwexstyle, dwstyle) = if params.kind == WindowKind::PopUp {
+        let (dwexstyle, mut dwstyle) = if params.kind == WindowKind::PopUp {
             (WS_EX_TOOLWINDOW, WINDOW_STYLE(0x0))
         } else {
             (
@@ -295,6 +295,10 @@ impl WindowsWindow {
                 WS_THICKFRAME | WS_SYSMENU | WS_MAXIMIZEBOX | WS_MINIMIZEBOX,
             )
         };
+        if !params.show {
+            dwstyle |= WS_MINIMIZE;
+        }
+
         let hinstance = get_module_handle();
         let display = if let Some(display_id) = params.display_id {
             // if we obtain a display_id, then this ID must be valid.
@@ -357,7 +361,12 @@ impl WindowsWindow {
             drop(lock);
             SetWindowPlacement(raw_hwnd, &placement)?;
         }
-        unsafe { ShowWindow(raw_hwnd, SW_SHOW).ok()? };
+
+        if params.show {
+            unsafe { ShowWindow(raw_hwnd, SW_SHOW).ok()? };
+        } else {
+            unsafe { ShowWindow(raw_hwnd, SW_HIDE).ok()? };
+        }
 
         Ok(Self(state_ptr))
     }