feat: rewrite remote.py as Rust CLI binary (crates/cli)

crates/cli/build.rs

@@ -0,0 +1,11 @@
+fn main() {
+    // Embed git commit hash at build time
+    let output = std::process::Command::new("git")
+        .args(["log", "-1", "--format=%h"])
+        .output();
+    let commit = match output {
+        Ok(o) => String::from_utf8_lossy(&o.stdout).trim().to_string(),
+        Err(_) => "unknown".to_string(),
+    };
+    println!("cargo:rustc-env=GIT_COMMIT={commit}");
+}