fix(windows): bump windows-sys to 0.59 (#5139)

The workspace `windows-sys` constraint was pinned to 0.52 while the
Windows source uses APIs and namespaces from 0.59 (e.g. WriteFile in
Win32::Storage::FileSystem). CI built fine because Cargo.lock pinned
0.59, but downstream `cargo install`/`cargo binstall` did fresh
resolution and selected 0.52, breaking the build for users on Windows.

Align the manifest with the code:
- Bump workspace dep `windows-sys` from 0.52 to 0.59.
- HANDLE is now `*mut c_void` instead of `isize`: replace
  `handle == 0` / `!= 0` with `is_null()`, initialise HANDLE locals
  with `std::ptr::null_mut()`, and pass `null_mut()` as the
  hTemplateFile argument to CreateFileW.
- Pass the process HANDLE through the exit-monitor thread as `usize`
  (raw pointers are not Send; OS handles are safe to use cross-thread).
- Note: HPCON is still `isize` in 0.59, so its zero-init is unchanged.

1 files changed, 2 insertions, 2 deletions

diff --git a/zellij-client/src/stdin_handler_windows.rs b/zellij-client/src/stdin_handler_windows.rs
index d6eba7cb..d22c790f 100644
--- a/zellij-client/src/stdin_handler_windows.rs
+++ b/zellij-client/src/stdin_handler_windows.rs
@@ -29,7 +29,7 @@ static ORIGINAL_CONSOLE_MODE: OnceLock<u32> = OnceLock::new();
 pub(crate) fn enable_vt_input() -> bool {
     unsafe {
         let handle = GetStdHandle(STD_INPUT_HANDLE);
-        if handle == 0 || handle == INVALID_HANDLE_VALUE {
+        if handle.is_null() || handle == INVALID_HANDLE_VALUE {
             return false;
         }
         let mut mode: u32 = 0;
@@ -77,7 +77,7 @@ pub(crate) fn restore_vt_input() {
     if let Some(&original_mode) = ORIGINAL_CONSOLE_MODE.get() {
         unsafe {
             let handle = GetStdHandle(STD_INPUT_HANDLE);
-            if handle != 0 && handle != INVALID_HANDLE_VALUE {
+            if !handle.is_null() && handle != INVALID_HANDLE_VALUE {
                 SetConsoleMode(handle, original_mode);
             }
         }