Videos: a destroyed sprite silences its free video (#420)

- A sprite destroyed or switched off holds its video still and quiet
  at once, and plays on from there when worn again.
- A sprite only out of view keeps its video playing, heard in a game.
- Development counts 2074 checks.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Development.md

@@ -21,7 +21,7 @@ php tests/php/releases.test.php                               # the release stor
 php tests/php/files.test.php                                  # uploaded files in a folder per account (#344), the same way
 php tests/php/videos.test.php                                 # the video store, its queue and the worker (#402), with the
                                                               #   real ffmpeg: the CI image and feuerwerk-video have it
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 2073 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 2074 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 — a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result

Videos.md

@@ -84,8 +84,10 @@ image. Only the sprite's Texture row offers videos; a tile, a particle source an
 take pictures only.
 
 - **In the editor** a placed video plays in the scene view without sound, round and round, as a
-  preview. The sprite's PREVIEW in the inspector plays it too, placed or not. A video nothing
-  shows for 2 s is let go and starts over the next time it is shown.
+  preview. The sprite's PREVIEW in the inspector plays it too, placed or not. A sprite destroyed
+  or switched off holds its video still and quiet at once; worn again, it plays on from there. A
+  sprite only out of view keeps it playing, heard in a game. A video nothing wears for 2 s is let
+  go and starts over the next time it is shown.
 - **Play** starts every video over at its clip's start and lets it be heard at the video's
   Volume, along its links in the [Master routing](Sounds#master-routing). A pause holds it, Esc
   makes it a quiet preview again. A [released game](Concepts) does the same.