fix: set executable permission on CLI binary in Python wheel (#419)

* fix: set executable permission on CLI binary in Python wheel

The repack step in build-wheels.mjs was producing wheels where
copilot/bin/copilot had 0o644 (-rw-r--r--) permissions because
setuptools strips the executable bit when building package data.

After extracting the wheel for repack, restore chmod 0o755 on the
CLI binary so that zf.write() captures the correct permissions.
This ensures pip/uv install the binary as executable on Unix.

* Update python/scripts/build-wheels.mjs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: SteveSandersonMS

python/scripts/build-wheels.mjs

@@ -253,6 +253,11 @@ with tempfile.TemporaryDirectory() as tmpdir:
     with zipfile.ZipFile(src_wheel, 'r') as zf:
         zf.extractall(tmpdir)
     
+    # Restore executable bit on the CLI binary (setuptools strips it)
+    for bin_path in (tmpdir / 'copilot' / 'bin').iterdir():
+        if bin_path.name in ('copilot', 'copilot.exe'):
+            bin_path.chmod(0o755)
+    
     # Find and update WHEEL file
     wheel_info_dirs = list(tmpdir.glob('*.dist-info'))
     if not wheel_info_dirs: