v0.4.19: fix post-move publish race in VideoCache.download

Reviewer-flagged: v0.4.18 only checked epoch BEFORE Files.move. The window
between the move completing and READY.put / "완료" chat was still racy —
if /videoCache clear landed in that window, clearAll would epoch++ +
clear READY + delete files on disk, then the download thread would do
READY.put(url, finalPath) anyway, resurrecting a cleared entry and emitting
a stale "완료" message.

Add a second epoch check immediately AFTER Files.move(): if the epoch
changed, delete finalPath and return without publishing. The pre-move
check is kept too — it lets the common cancel-during-read case skip the
wasted move/delete round-trip.

gradle.properties

@@ -5,7 +5,7 @@ org.gradle.configuration-cache=false
 
 # Mod
 mod_id=video_player
-mod_version=0.4.18
+mod_version=0.4.19
 maven_group=com.ejclaw.videoplayer
 archives_base_name=video_player
 

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

@@ -340,11 +340,10 @@ public final class VideoCache {
                 return;
             }
 
-            // Final cancellation check before publishing. If clearAll ran during the read
-            // loop's last iteration (after the loop check, before this point), we still
-            // refuse to publish — otherwise we'd resurrect a cache entry post-clear.
+            // Pre-move cancellation check. If clearAll ran during the read loop, abort
+            // before promoting .part to final — saves a wasted move + delete.
             if (CACHE_EPOCH.get() != startEpoch) {
-                VideoPlayerMod.LOG.info("[{}] preload: cancelled at publish (clearAll ran) — {}",
+                VideoPlayerMod.LOG.info("[{}] preload: cancelled before move (clearAll ran) — {}",
                     VideoPlayerMod.MOD_ID, url);
                 try { Files.deleteIfExists(partPath); } catch (Throwable ignored) {}
                 return;
@@ -352,6 +351,21 @@ public final class VideoCache {
 
             Files.move(partPath, finalPath, StandardCopyOption.REPLACE_EXISTING,
                 StandardCopyOption.ATOMIC_MOVE);
+
+            // Post-move cancellation check. clearAll() may have run between the pre-move
+            // check above and the move itself — in that case clearAll's directory scan
+            // either missed our file (it didn't exist yet) or saw the .part and skipped /
+            // failed to delete it. Either way, finalPath now exists on disk but the
+            // user-visible cache state is "cleared", so we must delete the file and skip
+            // both the READY.put and the "완료" chat. Without this check, a clear right at
+            // this window leaves a resurrected file in READY and a stale "완료" message.
+            if (CACHE_EPOCH.get() != startEpoch) {
+                VideoPlayerMod.LOG.info("[{}] preload: cancelled after move (clearAll ran) — {}",
+                    VideoPlayerMod.MOD_ID, url);
+                try { Files.deleteIfExists(finalPath); } catch (Throwable ignored) {}
+                return;
+            }
+
             READY.put(url, finalPath);
             VideoPlayerMod.LOG.info("[{}] preload: cached {} ({} bytes) -> {}",
                 VideoPlayerMod.MOD_ID, url, total, finalPath.getFileName());