server: clean up static assets handling (#24550)

* server: clean up static assets handling

* nits

* simplify file name handling, use static file name everywhere

* cmake/ui : bundle UI assets in an archive

* ui : run prettier on post-build.js

---------

Co-authored-by: Alde Rojas <hello@alde.dev>

tools/ui/scripts/post-build.js

@@ -0,0 +1,40 @@
+#!/usr/bin/env node
+// Post-build: copy hashed/nested assets to predictable flat names.
+// No file content is modified — the C++ server handles routing hashed URLs
+// to the correct stored asset at runtime.
+//
+// Copies:
+//   _app/immutable/bundle.HASH.js         -> bundle.js
+//   _app/immutable/assets/bundle.HASH.css -> bundle.css
+//   workbox-HEXHASH.js                    -> workbox.js
+//   _app/version.json                     -> version.json
+
+import fs from 'fs';
+import path from 'path';
+
+const outDir = process.env.LLAMA_UI_OUT_DIR ?? './dist';
+
+function findOne(dir, pattern) {
+	const files = fs.readdirSync(dir).filter((f) => pattern.test(f));
+	if (files.length === 0) throw new Error(`post-build: no file matching ${pattern} in ${dir}`);
+	return path.join(dir, files[0]);
+}
+
+function copyFlat(src, destName) {
+	const dest = path.join(outDir, destName);
+	fs.copyFileSync(src, dest);
+	console.log(`post-build: ${path.relative(outDir, src)} -> ${destName}`);
+}
+
+const bundleJs = findOne(path.join(outDir, '_app/immutable'), /^bundle\.[^.]+\.js$/);
+const bundleCss = findOne(path.join(outDir, '_app/immutable/assets'), /^bundle\.[^.]+\.css$/);
+const workbox = findOne(outDir, /^workbox-[0-9a-f]+\.js$/);
+
+copyFlat(bundleJs, 'bundle.js');
+copyFlat(bundleCss, 'bundle.css');
+copyFlat(workbox, 'workbox.js');
+
+const versionSrc = path.join(outDir, '_app/version.json');
+if (fs.existsSync(versionSrc)) {
+	copyFlat(versionSrc, 'version.json');
+}

tools/ui/scripts/vite-plugin-build-info.ts

@@ -23,8 +23,7 @@ export function buildInfoPlugin(): Plugin {
 					if (processed) return;
 					processed = true;
 
-					const buildNumber = process.env.LLAMA_BUILD_NUMBER;
-					if (!buildNumber) return;
+					const buildNumber = process.env.LLAMA_BUILD_NUMBER || 'b0000';
 
 					const outDir = resolve(OUTPUT_DIR);
 					const indexPath = resolve(outDir, 'index.html');