Implement movie surface stop-time queries

engine/Age.Engine/Hosting/IHost.cs

@@ -15,6 +15,8 @@ public readonly record struct SurfaceRectFill(
 
 public interface IHost
 {
+    /// <summary>Report a recoverable runtime discrepancy while allowing script execution to continue.</summary>
+    void ReportWarning(string message) => System.Console.Error.WriteLine(message);
     // Script-local resource ids resolve against the currently executing frame's SYS4INI section.
     // Interactive hosts track this stack; headless hosts may keep the no-op/default identity behavior.
     void EnterScriptContext(string scriptName) { }
@@ -111,7 +113,10 @@ public interface IHost
     void FadeBgm(int targetPercent, long durationMs) { }
     // Native op 0x236 binds a DirectShow movie decoder to an existing retained texture surface.
     // Playback is non-modal: the VM advances to the following instruction while the host publishes frames.
-    void PlayMovieToSurface(long resourceId, int surfaceSlot, long movieFlags, long syncMask) { }
+    /// <returns>The initialized movie graph's stop position in truncated integer milliseconds, or null
+    /// when the host could not obtain usable timing metadata. Native op 0x23f queries this state
+    /// immediately after 0x236 returns.</returns>
+    long? PlayMovieToSurface(long resourceId, int surfaceSlot, long movieFlags, long syncMask) => null;
     // Native op 0x20f uses a universal raw-catalog id and parks script execution until the movie
     // reaches EOF or the player cancels it. The decoder remains asynchronous; the interactive host
     // owns the modal wait so its render loop can continue publishing frames.