fix(remux): preserve encrypted HLS and test protocol restrictions

Allow nested crypto for encrypted HTTP HLS while rejecting top-level protocol wrappers and local-file access. Replace the HLS-only http_persistent option with HTTP multiple_requests across probe/remux/transcode paths, fixing the raw HTTP regression introduced by #124. Add real FFmpeg regression tests and PR CI.

package.json

@@ -6,7 +6,8 @@
     "main": "server/index.js",
     "scripts": {
         "start": "node server/index.js",
-        "dev": "node --watch server/index.js"
+        "dev": "node --watch server/index.js",
+        "test": "node --test"
     },
     "dependencies": {
         "@ffprobe-installer/ffprobe": "^2.1.2",
@@ -29,4 +30,4 @@
     "engines": {
         "node": ">=18.0.0"
     }
-}
+}