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, 1 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd712cde..058c29c7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 * feat: allow tabs to have different sizes if clients aren't focused on the same one (https://github.com/zellij-org/zellij/pull/5133)
+* fix(windows): bump windows-sys to 0.59 to align manifest with code, fixing source builds via `cargo install`/`cargo binstall` (https://github.com/zellij-org/zellij/pull/5139)
 
 ## [0.44.2] - 2026-05-05
 * fix: idle CPU + disk i/o, CommandChanged plugin Event, GetSessionList plugin command (https://github.com/zellij-org/zellij/pull/5063)