Describe faint clips and the embedded assets a song shares (#357)

- Sounds: the clip area shrinks with the wave when zoomed out, a click
  beside the picked clip picks the sound, and the clips not picked lie
  faint over the wave.
- Songs: an embedded sound, pattern or sound FX is shared by the places
  of its song and goes with the last one. A paste into another song
  makes one copy. The picks offer what the song keeps.
- Development: 1898 checks.

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

Development.md

@@ -19,7 +19,7 @@ php tests/php/accounts.test.php                               # the API's accoun
 php tests/php/snapshots.test.php                              # the snapshot store (#231), the same way
 php tests/php/releases.test.php                               # the release store (#266), the same way
 php tests/php/files.test.php                                  # uploaded files in a folder per account (#344), the same way
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1897 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1898 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

Songs.md

@@ -222,18 +222,22 @@ names of the inputs show once recording has been allowed, and the browser keeps
 A sound, a pattern or a sound FX can belong to one song instead of the project (#355). A take is
 one. It is edited like any other: a double-click on its item opens it in its tab, where its
 [clips](Sounds#clips) are made and cut as always, and the tab's title has the song's name in front
-of its own. But it has no row in the Assets panel, no picker offers it (not the inspector, not a
-node), and its name only has to be free within the song. Only the *Sound* row of its own item
-offers it and its clips, under a line after the project's sounds.
+of its own. But it has no row in the Assets panel, no picker outside its song offers it (not a
+node, not another song), and its name only has to be free within the song. Within the song the
+picks offer it under a line after the project's assets: the *Sound* row of an item the song's
+sounds and their clips, the *Pattern* row its patterns, every sound FX pick its sound FX.
 
-- **One user.** An embedded asset is used by exactly one place of its song: an item, a track or the
-  song itself. A split, `Ctrl+D` and a paste give every new item a copy of its own, so setting one
-  half of a split take to another clip leaves the other half as it was. A copy gets copies of the
-  clips, and an item on a clip plays the same clip of its copy. The audio file is not copied:
-  files are stored by their content.
-- **It goes with its user.** Deleting the item, its track or the song deletes the embedded asset
-  in the same undo step. A copied item keeps it in the clipboard, so a paste after the delete brings
-  it back. *Duplicate* on the song copies everything it keeps to itself.
+- **Shared within the song (#357).** The places of a song share what it keeps: the song itself,
+  its tracks and its items. A split and `Ctrl+D` leave both items on the same take, so the four
+  clips of one take serve four items, and a cut made in the Sound tab is heard on every item
+  playing that clip. To bend one item alone, *Make project asset* and *Embed a copy* still make a
+  copy.
+- **A paste into another song** gives that song a copy, one for all the items naming it. A copy
+  gets copies of the clips, and an item on a clip plays the same clip of its copy. The audio file
+  is not copied: files are stored by their content.
+- **It goes with its last user.** Once no item, track or the song names it any more, the embedded
+  asset is deleted in the same undo step. A copied item keeps it in the clipboard, so a paste after
+  the delete brings it back. *Duplicate* on the song copies everything it keeps to itself.
 - A click on its name in the inspector lights up its song in the Assets panel.
 - In the Sound tab of an embedded sound the rows *Loop* and *Bus* are left out: in a song an item
   repeats its sound as long as it is, and the track decides where it goes.
@@ -258,8 +262,9 @@ song) and an item for it, one undo step, and opens it in the Pattern tab.
 
 ### A sound FX of its own
 
-Every pick of a sound FX in a song ends with a few entries for one that only that place has: the
-**Sound FX** row of the song, of a track and of an item, and the menu of a track's **FX** button.
+Every pick of a sound FX in a song ends with the sound FX the song keeps, with the mark in front,
+and a few entries to make one: the **Sound FX** row of the song, of a track and of an item, and
+the menu of a track's **FX** button. Picking one the song keeps lets this place share it.
 
 - **Create sound FX** makes *Sound FX 1*, 2 … (numbered per song) with its Input wired to its
   Output, so it lets the sound through until something is put in between. The place picks it and
@@ -268,8 +273,8 @@ Every pick of a sound FX in a song ends with a few entries for one that only tha
   under the same name, to bend without touching the original.
 - While the place names its own, the menu shows it with the mark in front and offers **Edit sound
   FX** (opens it, as a double-click on its name in the inspector does) and **Make project asset**.
-- Picking anything else, *None* or another sound FX, lets it go in the same undo step. That holds
-  for the song's own row too.
+- Picking anything else, *None* or another sound FX, lets it go. If this place was the last one
+  naming it, it goes in the same undo step. That holds for the song's own row too.
 
 ## Playing one in a game
 

Sounds.md

@@ -78,9 +78,12 @@ counts in it — `length`, the rounds of a song item and their waveform, a Sampl
 Pitch.
 
 - **Drag in the strip** to make a new clip from where you pressed. It is picked right away.
-- **Click a band** to pick its clip, **click beside the bands** to pick the sound again. The
-  picked clip's band is lit, and its stretch stands between **two handles** in the wave. What lies
-  outside is darker. With no clip picked the whole file is bright and has no handles.
+- **Click a band** to pick its clip, **click beside the bands** to pick the sound again. A
+  **click in the wave beside the picked clip** picks the sound too. The picked clip's band is lit,
+  and its stretch stands between **two handles** in the wave. What lies outside is darker. With no
+  clip picked the whole file is bright and has no handles.
+- **The other clips** stay faint in the wave, a pale tint with a thin edge over their stretch, so
+  you see where they lie while you work on one.
 - **Drag a handle** to move that edge of the picked clip. **Drag anywhere else** in the wave to
   span it anew from where you pressed. With no clip picked, a drag in the wave makes a new clip, as
   in the strip. One drag is one undo step, the two edges together. An edge cannot pass the other.
@@ -106,7 +109,8 @@ Pitch.
 - Left of the wave stands a **level scale** in dB, a mark every 6 dB (#357). The **wheel over the
   scale** zooms the wave's height, from a quarter to 16 times: zoomed out, a full-scale wave leaves
   room above and below it; zoomed in, quiet stretches get tall enough to see, and what is louder
-  stops at the edge. The fade ramps grow with the wave. **Fit** brings back the whole file at its
+  stops at the edge. The fade ramps grow with the wave. Zoomed out, the bright file, the picked
+  clip and its handles shrink with it to the height of a full-scale wave. **Fit** brings back the whole file at its
   full height.
 - A stereo file shows **one** wave, the loudest of its channels; it plays in stereo.
 - The header's readout says how long the picked clip is, and of how long a file.