Windows and Linux build environments; check clean on both (E-01)

MuPDF builds with MSBuild on Windows (/MT, OpenSSL from vcpkg);
Git for Windows' MinGit stands in for the source build there. CEF
loads from where libcef lives and sets its API version first on
every platform. File identity on Windows compares volume and index.
The checkout and reference/ keep LF on Windows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ely-platform/src/git.rs

@@ -14,6 +14,12 @@ pub const PROGRAM: &str = "git";
 /// The oldest system Git counted as verified (user decision).
 pub const LEAST: (u32, u32) = (2, 40);
 
+/// Git inside a Git install: MinGit's on Windows.
+#[cfg(windows)]
+const GIT: &str = "cmd/git.exe";
+#[cfg(not(windows))]
+const GIT: &str = "bin/git";
+
 /// `ELY_GIT`, ElyTree's setting, else Ely's own Git.
 pub fn locate() -> io::Result<(PathBuf, bool)> {
     if let Some(path) = std::env::var_os("ELY_GIT") {
@@ -62,12 +68,12 @@ pub fn system_version(path: &Path) -> io::Result<String> {
 /// Beside `dir`, in its bundle, in ElyTree's, or built.
 fn own(dir: &Path) -> PathBuf {
     // ElyTree carries Git; the other apps use its copy.
-    let tree = format!("../../../{}.app/Contents/Resources/git/bin/git", AppId::Tree.name());
-    let built = Path::new(env!("CARGO_MANIFEST_DIR")).join("../../engines/git/bin/git");
+    let tree = format!("../../../{}.app/Contents/Resources/git", AppId::Tree.name());
+    let built = Path::new(env!("CARGO_MANIFEST_DIR")).join("../../engines/git").join(GIT);
     [
-        dir.join("git/bin/git"),
-        dir.join("../Resources/git/bin/git"),
-        dir.join(tree),
+        dir.join("git").join(GIT),
+        dir.join("../Resources/git").join(GIT),
+        dir.join(tree).join(GIT),
     ]
     .into_iter()
     .find(|path| path.is_file())
@@ -113,17 +119,17 @@ mod tests {
         assert_eq!(super::parse_version("hello"), None);
     }
 
-    use super::own;
+    use super::{GIT, own};
 
     #[test]
     fn apps_beside_elytree_use_its_git() {
         let apps = tempfile::tempdir().expect("a temp dir");
         let mark = apps.path().join("ElyMark.app/Contents/MacOS");
-        let git = apps.path().join("ElyTree.app/Contents/Resources/git/bin");
+        let git = apps.path().join("ElyTree.app/Contents/Resources/git").join(GIT);
         std::fs::create_dir_all(&mark).expect("ElyMark");
-        assert!(own(&mark).ends_with("engines/git/bin/git"));
-        std::fs::create_dir_all(&git).expect("ElyTree's Git");
-        std::fs::write(git.join("git"), "").expect("git");
-        assert_eq!(own(&mark), mark.join("../../../ElyTree.app/Contents/Resources/git/bin/git"));
+        assert!(own(&mark).ends_with(std::path::Path::new("engines/git").join(GIT)));
+        std::fs::create_dir_all(git.parent().expect("a folder")).expect("ElyTree's Git");
+        std::fs::write(&git, "").expect("git");
+        assert_eq!(own(&mark), mark.join("../../../ElyTree.app/Contents/Resources/git").join(GIT));
     }
 }