Add remastered OGV cutscene playback with MIDI music sync

[elliotttate]

Summary

• Adds support for playing the remastered OGV (Ogg Theora) video cutscenes from the Dark Forces Remaster, with the original iMUSE MIDI music synchronized to match
• Pre-scans the original FILM cutscene chain to extract CUST actor cue points and their timestamps, then scales them to OGV duration so MIDI transitions fire at the correct visual moments for all cutscenes
• Includes SRT subtitle support with the existing accessibility/caption system, OGV audio mixing alongside MIDI, and a user-facing toggle in the settings UI
• Builds are gated behind ENABLE_OGV_CUTSCENES (CMake) / preprocessor define so it has zero impact when disabled

Details

• New files: ogvPlayer.cpp/h (Theora/Vorbis decoding + OpenGL YUV rendering), remasterCutscenes.cpp/h (OGV path resolution from remaster install), srtParser.cpp/h (subtitle loading)
• Modified: cutscene.cpp (OGV playback path + FILM-driven cue scheduling), audioSystem (PCM mixing for OGV audio), renderBackend (fullscreen quad for video frames), settings (remaster cutscene toggle), frontEndUi (settings checkbox)
• CMakeLists.txt adds optional theoradec, ogg, vorbis dependencies behind the option flag
• vcxproj updated for Windows builds with bundled ogg/theora/vorbis libs

Test plan

• Play intro cutscene (scene 10) — music should start and transition at the same moments as the original LFD cutscene
• Skip cutscene with ESC/Space/Enter — music should stop, no leftover state
• Play with remaster cutscenes disabled in settings — original LFD path should be unaffected
• Build without ENABLE_OGV_CUTSCENES — should compile cleanly with no OGV code included
• Build on Linux with CMake + the theora/ogg/vorbis packages installed