Serve static files at /static and set JS MIME type

Add strings import for .js detection. Register an additional FileServer
at "/static/" to expose static files under that prefix. In the
FileServer handler, set Content-Type to "application/javascript" for .js
requests.

cmd/app/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"net/http"
+	"strings"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
@@ -17,9 +18,10 @@ func main() {
 
 	// Register the hello world handler at the root path
 
-	// Serve static HTML files from the "static" directory
-	// (e.g., /static/index.html will be accessible at /static/index.html)
+	// Serve static HTML files from the "static" directory at the root
 	FileServer(r, "/", http.Dir("./static"))
+	// Also serve the same files under the "/static" URL prefix
+	FileServer(r, "/static/", http.Dir("./static"))
 
 	// Start the HTTP server
 	http.ListenAndServe(":8080", r)
@@ -36,6 +38,10 @@ func FileServer(r chi.Router, publicPath string, root http.FileSystem) {
 	}
 	fs := http.StripPrefix(publicPath, http.FileServer(root))
 	r.Get(publicPath+"*", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Set correct MIME type for JavaScript files
+		if strings.HasSuffix(r.URL.Path, ".js") {
+			w.Header().Set("Content-Type", "application/javascript")
+		}
 		fs.ServeHTTP(w, r)
 	}))
 }