Implement auto-update routine

build.rs

@@ -19,6 +19,16 @@
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=resources/icon.ico");
+    // winres derives FileVersion / ProductVersion from `CARGO_PKG_VERSION`,
+    // which is sourced from `Cargo.toml`. Without this directive, cargo
+    // happily skips the build script when only the version field changed
+    // (build.rs and the .ico are byte-identical), and the resulting EXE
+    // ships with stale "FileVersion" / "ProductVersion" properties — the
+    // binary itself is the new build, but Explorer's Properties dialog
+    // and any Authenticode tooling that reads the resource block see the
+    // previous version. Forcing a re-run on Cargo.toml changes is cheap
+    // (winres compile is sub-second) and bulletproof.
+    println!("cargo:rerun-if-changed=Cargo.toml");
 
     let target_os = std::env::var("CARGO_CFG_TARGET_OS").unwrap_or_default();
     if target_os != "windows" {