install missing libraries and font

Signed-off-by: Kenneth Obsequio <k80308392@gmail.com>

services/certificate.service.js

@@ -21,6 +21,11 @@ const execFileAsync = promisify(execFile);
 const TEMPLATE_PATH = path.join(__dirname, '../templates/certificate.typ');
 const FONT_PATH     = path.join(__dirname, '../templates/fonts/Arimo');
 
+// The Docker image gets `typst` on PATH via COPY --from=typst. Bare-metal
+// deploys (no Docker involved) don't have that, so TYPST_BIN lets ops point
+// at a manually-installed binary instead.
+const TYPST_BIN = process.env.TYPST_BIN || 'typst';
+
 /**
  * @param {{
  *   name:        string,
@@ -52,7 +57,7 @@ async function generateCertificate({ name, course, date, cert_no, ref_no, instru
   if (length)      args.push('--input', `length=${length}`);
 
   try {
-    await execFileAsync('typst', args);
+    await execFileAsync(TYPST_BIN, args);
     return await fs.readFile(outPath);
   } finally {
     await fs.unlink(outPath).catch(() => {});