feat: play resolved Miruro HLS with external VTT and stable episode progress

Sources/Core/network_input.hpp

@@ -17,6 +17,7 @@ extern "C" {
 #include <mutex>
 #include <new>
 #include <stdexcept>
+#include <string>
 #include <thread>
 
 namespace playback {
@@ -49,6 +50,9 @@ class NetworkInput {
 public:
     static constexpr double aheadSeconds = 60, behindSeconds = 30;
     AVFormatContext *format = nullptr;
+    // Resolved sources bind credentials to their original origin for all HLS I/O.
+    std::string headerOrigin;
+    std::string requestHeaders;
 
     NetworkInput(const std::atomic<bool> &stopping, const std::atomic<uint64_t> &epoch,
                  uint64_t activeEpoch, std::condition_variable &playerWake, StreamCacheBudget &budget)