Videos: the ruler stops playback and Play starts at the playhead

- A click into the ruler stops the playback and resets the button.
- Play starts at the playhead when it lies inside the clip.
- Development names 2041 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 game-maker-video have it
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 2039 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 2041 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

@@ -51,9 +51,10 @@ The clip gestures are the same as in the [Sound tab](Sounds), with the track in
 - **With a clip picked**, it stands in the track between two handles. **Dragging a handle** moves
   that edge, **dragging its band** in the strip moves the whole clip, its length kept. **Any other
   drag does nothing.** The picture follows the edge or the start being dragged.
-- **A click in the ruler** shows that moment.
+- **A click in the ruler** shows that moment, and stops a play.
 - **Play** (or **Space**) plays the picked clip, else the whole video, with its sound and its
-  Loop. The playhead runs along the ruler.
+  Loop. It starts at the playhead when that stands inside, else at the start, so Stop and Play
+  go on where it stopped. The playhead runs along the ruler.
 - The wheel zooms the time, the middle button pans, **Fit** shows the whole video. A wheel step
   and Fit are shown as the short zoom transition of the other tabs (see [Concepts](Concepts)).
 - **Download** saves the MP4 the server made, under the asset's name.