Add --quiet flag to build.mjs for cleaner 'just dev' output

scripts/build.mjs

@@ -6,6 +6,7 @@
  *   node scripts/build.mjs          # build everything
  *   node scripts/build.mjs --css    # CSS only
  *   node scripts/build.mjs --js     # JS only
+ *   node scripts/build.mjs --quiet  # suppress per-file output, summary only
  *
  * Requires: npm install (lightningcss-cli, rolldown)
  */
@@ -21,14 +22,16 @@ const root = resolve(__dirname, "..");
 const args = process.argv.slice(2);
 const onlyCss = args.includes("--css");
 const onlyJs = args.includes("--js");
+const quiet = args.includes("--quiet");
 const buildAll = !onlyCss && !onlyJs;
 
 function run(label, cmd) {
-  console.log(`\n📦 ${label}…`);
-  execSync(cmd, {
-    cwd: root,
-    stdio: "inherit",
-  });
+  if (quiet) {
+    execSync(cmd, { cwd: root, stdio: "pipe" });
+  } else {
+    console.log(`\n📦 ${label}…`);
+    execSync(cmd, { cwd: root, stdio: "inherit" });
+  }
 }
 
 // Ensure node_modules exist
@@ -49,4 +52,8 @@ if (buildAll || onlyJs) {
   run("Building JS bundles", "node scripts/build-js.mjs");
 }
 
-console.log("\n✅ Build complete\n");
+if (quiet) {
+  console.log("✅ CSS/JS rebuilt");
+} else {
+  console.log("\n✅ Build complete\n");
+}