build: simplify build & run process of FE files

use external bun packages to bundle files, run this package in the
build.rs script

build.rs

@@ -1,5 +1,33 @@
-fn main() {
-    // only enable in production build
-    #[cfg(not(debug_assertions))]
-    minijinja_embed::embed_templates!("dist");
+use std::io::Write;
+use std::process::Command;
+use std::{env, io};
+
+fn cmd(cmd: &mut Command) {
+    let output = cmd.output().unwrap();
+
+    let _ = io::stdout().write_all(&output.stdout);
+    if !output.status.success() {
+        let _ = io::stderr().write_all(&output.stderr);
+        panic!("\nFailed to run command\n");
+    }
+}
+
+fn main() {
+    let out_dir = env::var("OUT_DIR").unwrap();
+
+    cmd(Command::new("bun").args(["install"]));
+    cmd(Command::new("bun").args([
+        "run",
+        "tmpl-build-and-load",
+        "--outdir",
+        out_dir.as_str(),
+        "--globs",
+        "frontend/templates/**/*.html",
+    ]));
+
+    println!("Build completed successfully!");
+
+    println!("cargo::rerun-if-changed=build.rs");
+    println!("cargo::rerun-if-changed=package.json");
+    println!("cargo::rerun-if-changed=frontend");
 }