feat: add remark modified time plugin

src/plugins/remark/modified-time.mjs

@@ -0,0 +1,10 @@
+import { execSync } from "child_process";
+import { statSync } from "node:fs";
+
+export function remarkModifiedTime() {
+    return function (tree, file) {
+        const filepath = file.history[0];
+        const result = execSync(`git log -1 --pretty="format:%cI" "${filepath}"`).toString() || statSync(filepath).mtime.toISOString();
+        file.data.astro.frontmatter.lastModified = result.toString();
+    };
+}