v0.4.29: delete promoted cache file on first epoch-mismatch in publishIfNotCancelled

If wipeOnShutdown runs between download's pre-move epoch check and the
atomic Files.move, the wipe's directory scan misses the just-promoted
final file. The first epoch-mismatch branch in publishIfNotCancelled was
returning without deleting, leaking the file across sessions. Delete on
the first branch too.

src/main/java/com/ejclaw/videoplayer/client/playback/VideoCache.java

@@ -284,7 +284,13 @@ public final class VideoCache {
      *         caller's work was cancelled and {@code path} has been cleaned up.
      */
     private static boolean publishIfNotCancelled(String url, Path path, long startEpoch) {
-        if (CACHE_EPOCH.get() != startEpoch) return false;
+        // If the wipe ran between download's pre-move epoch check and Files.move, its
+        // directory scan won't have seen this just-promoted file. We must delete it here,
+        // not just bail — otherwise the freshly-moved final file leaks across shutdown.
+        if (CACHE_EPOCH.get() != startEpoch) {
+            try { Files.deleteIfExists(path); } catch (Throwable ignored) {}
+            return false;
+        }
         READY.put(url, path);
         if (CACHE_EPOCH.get() != startEpoch) {
             READY.remove(url, path);