ci: add FFmpeg preflight workflow and helpers

tools/copy-ffmpeg.js

@@ -41,6 +41,31 @@ function resolveSource() {
 
 function main() {
   const name = platformBinName();
+  // If CI or prior steps already placed ffmpeg into resources, prefer that and skip copying.
+  const existingInResources = path.join(resourcesDir, name);
+  if (exists(existingInResources)) {
+    console.log(`FFmpeg already present in resources: ${existingInResources} — skipping copy.`);
+    process.exit(0);
+  }
+  // Also search recursively in resources for any ffmpeg-like file (robustness for nested archives)
+  if (exists(resourcesDir)) {
+    const files = fs.readdirSync(resourcesDir, { withFileTypes: true });
+    const found = (function findRec(dir) {
+      for (const f of fs.readdirSync(dir, { withFileTypes: true })) {
+        const p = path.join(dir, f.name);
+        if (f.isFile() && f.name.toLowerCase().startsWith('ffmpeg')) return p;
+        if (f.isDirectory()) {
+          const r = findRec(p);
+          if (r) return r;
+        }
+      }
+      return null;
+    })(resourcesDir);
+    if (found) {
+      console.log(`Found ffmpeg in resources at ${found} — skipping copy.`);
+      process.exit(0);
+    }
+  }
   const src = resolveSource();
   if (!src) {
     console.log('FFmpeg not provided; skipping copy (set RADIOPLAYER_FFMPEG or place it under tools/ffmpeg/).');