Describe the Envelope node as a device with its curve (#388)

- Instruments: a paragraph on the device under Envelopes.
- Architecture: EnvelopePanel, EnvelopeFace and envelopeView.
- Development: 1963 checks.

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

Architecture.md

@@ -432,7 +432,9 @@ src/editor/soundfx/    SoundFxEditor (#311: the graph, a sound to try it on, Pla
                        the Gain as an orange plate with one knob, `drawPlate` shared with the Compressor),
                        ChipPanel + ChipFace + chipView (#386: the Chip of an instrument as a device, its
                        wave and its pitch over a note worked out apart from the drawing, the
-                       Compressor's `Lever` for "follow note"), nodeParamDrag (a knob's drag as one undo
+                       Compressor's `Lever` for "follow note"), EnvelopePanel + EnvelopeFace + envelopeView
+                       (#388: the Envelope as a device, its curve over a note with squeezed time worked
+                       out apart from the drawing), nodeParamDrag (a knob's drag as one undo
                        step, for the tab and the node), nodeTabs (which nodes open a tab of their own)
 src/editor/instrument/ InstrumentEditor (#331: the graph over the keys, Preset, Randomize, Mutate, Audition),
                        PianoKeyboard + keys (the keys drawn, played by the pointer and the computer keyboard)

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                 # 1962 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1963 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

Instruments.md

@@ -153,6 +153,22 @@ sound as it is.
   at 0.65 s and 0.0005 at 0.8 s, released mid-attack at 0.05 s it fell from 0.5 to 0.05 at 0.15 s.
   A Gain moved from 0.25 to 1 by that curve was 0.5 halfway up. Live, a looped note of 0.2 s
   through an Envelope with a release of 1 s was gone 1.32 s after it started, read every 150 ms.
+- **The node is a device** (#388), 520x280, a plate in pale sea green. The inputs are on the left,
+  `out` and `value` on the right, and everything is set right in the graph:
+  - a dark screen, **Level over a note**, draws the curve in amber: a letter above each stage
+    (A, D, S, R), its time below it, and the sustain in percent above its line. The time is
+    squeezed so a short attack still shows beside a long release: each stage is as wide as the
+    root of its seconds, the hold a fixed fifth. With *Sustain* 0 there is no hold and no release,
+    and the screen says *Note ends*. While a link takes `value`, the bezel says what it moves
+    between (`VALUE 400 TO 3500`);
+  - a **chrome knob** for *Attack*, *Decay*, *Sustain* and *Release*. A drag is one undo step, a
+    double-click goes back to the default, the wheel zooms the graph. The times give their first
+    second most of the turn (5 ms an eighth of the way, 1 s not quite half);
+  - **From** and **To** as fields, typed in or scrubbed sideways, since they have no range a knob
+    could turn through.
+
+  The decay at *Sustain* 1 and From/To while nothing takes `value` are faded; a connected number is
+  greyed and can not be changed. The screen is drawn from the settings, not listened to.
 
 ## Chips