fix: preserve app identity through FFmpeg preflight

Sources/App/Bootstrap.swift

@@ -9,13 +9,17 @@ enum TerebiBootstrap {
         if let error = FFmpegRuntime.error(for: app) {
             fail(error)
         }
-        let payload = app.appendingPathComponent("Contents/MacOS/terebi-player")
-        let errorCode = payload.path.withCString { path in
-            _ = execv(path, CommandLine.unsafeArgv)
-            return errno
+        let payload = app.appendingPathComponent("Contents/Frameworks/libterebi-player.dylib")
+        guard let library = dlopen(payload.path, RTLD_NOW | RTLD_LOCAL) else {
+            let detail = dlerror().map { String(cString: $0) } ?? "The dynamic loader could not load the player."
+            fail("Could not load the player: \(detail)\n\nPlayer library: \(payload.path)\nRebuild and reinstall terebi.")
         }
-        let detail = String(cString: strerror(errorCode))
-        fail("Could not start the player: \(detail)\n\nPlayer executable: \(payload.path)\nRebuild and reinstall terebi.")
+        guard let entry = dlsym(library, "terebi_app_main") else {
+            fail("The player library is missing its application entry point. Rebuild and reinstall terebi.")
+        }
+        // Keep the declared app executable alive so LaunchServices retains its identity.
+        typealias PlayerMain = @convention(c) () -> Void
+        unsafeBitCast(entry, to: PlayerMain.self)()
     }
 
     private static func fail(_ message: String) -> Never {