Describe the Limiter node as a device that holds its reduction (#397)

- Sounds: the table row, and a part on the device under Compressor
  and Limiter. It covers the knobs, the lever, the lamp, the screen,
  how the capture is held and how the reduction is read.
- Architecture: LimiterPanel, LimiterFace and limiterView.
- Development: 1970 editor checks.

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

Architecture.md

@@ -443,7 +443,10 @@ src/editor/soundfx/    SoundFxEditor (#311: the graph, a sound to try it on, Pla
                        worked out apart from the drawing), SaturationPanel + SaturationFace +
                        saturationView (#396: the Saturation as a device, the wave a sine comes out as
                        and the heat it glows with worked out apart from the drawing; its type buttons
-                       are the Reverb's `PickButton`), nodeParamDrag (a knob's drag as one undo step, for the tab and the
+                       are the Reverb's `PickButton`), LimiterPanel + LimiterFace + limiterView (#397:
+                       the Limiter as a device, what it takes away read from its taps and caught from
+                       the start of a sound, held once it ends, worked out apart from the drawing),
+                       nodeParamDrag (a knob's drag as one undo step, for the tab and the
                        node, several settings at once since #389), nodeTabs (which nodes open a tab of
                        their own)
 src/editor/instrument/ InstrumentEditor (#331: the graph over the keys, Preset, Randomize, Mutate, Audition),

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                 # 1969 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1970 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

Sounds.md

@@ -435,7 +435,7 @@ response of a Reverb, and as what the Sound FX tab tries out. Its row means noth
 | **Flanger** | Blends the sound with a copy a few ms late: the jet sound of a flanger, and what sfxr calls its phaser. `offset` is how late the copy is (1 ms by default), `sweep` moves that on by so many ms a second from the start of the sound (0), an LFO adds up to `depth` ms (2) `rate` times a second (0.25 Hz). `feedback` (0.5) and `wet` (1) as on the Phaser. See [below](#phaser-and-flanger). |
 | **Pan** | Moves the sound left or right: `pan` -1 is all left, 1 all right, 0 (the default) leaves it in the middle. A mono sound is spread on both sides and then moved (each side 0.707 at 0). A stereo sound keeps the side it goes to and the other side moves over into it, as Web Audio's `StereoPannerNode` does: at 1 both sides are heard on the right. In an [instrument](Instruments#envelopes) an Envelope can move it. Measured (e2e 34, Chrome offline): a mono sine at 0.5 came out 0.5 / 0 at -1 and 0.354 / 0.354 at 0, a stereo one at 0.5 came out 0.354 / 0.854. In the graph the node is drawn as the Gain's device in cyan (#392), with one knob for `Pan`: the middle stands straight up, the turn goes evenly to *L* and *R* engraved at its ends. A linked `Pan` greys the knob. |
 | **Compressor** | Squeezes the loudness together: what goes above `threshold` (-24 dB by default) comes out only 1/`ratio` (4) as much louder. `knee` (6 dB) eases into it, `attack` (0.003 s) and `release` (0.25 s) say how fast it turns down and lets go. `makeup` (0 dB) raises it afterwards. **Auto-gain** (off) gives back what it takes from a sound at -18 dB, with the makeup on top. The node is drawn as a device with a meter of what it takes away, and a double-click opens a tab with its curve and the level going in and out. See [below](#compressor-and-limiter). |
-| **Limiter** | Keeps every peak below `threshold` (-6 dB): it looks 5 ms ahead, so even a sudden peak never gets through, and comes back up in `release` (0.1 s). **Auto-gain** (on) raises the limited sound to `ceiling` (-1 dB). Nothing ever goes above the ceiling. See [below](#compressor-and-limiter). |
+| **Limiter** | Keeps every peak below `threshold` (-6 dB): it looks 5 ms ahead, so even a sudden peak never gets through, and comes back up in `release` (0.1 s). **Auto-gain** (on) raises the limited sound to `ceiling` (-1 dB). Nothing ever goes above the ceiling. The node is drawn as a brick device whose screen holds how much it took away and when (#397). See [below](#compressor-and-limiter). |
 | **Saturation** | Bends the sound, from warmth to a hard distortion. **Type**: *Soft (tanh)* (the default), *Cubic*, *Hard clip*, *Tube*, *Fuzz*, *Foldback*, *Sine fold* or *Rectify*. `drive` (12 dB) is how hard the sound is pushed into it, `tone` (1) a low-pass after it from 1 kHz (0) to wide open (1). **Auto-gain** (on) keeps the bent sound about as loud as it came in, `output` (0 dB) is added on top. `wet` (1) how much of it is heard instead of the sound itself. The node is drawn as a copper device whose screen glows hotter the harder it is driven (#396). See [below](#saturation). |
 | **Tremolo** | Makes the volume swing `rate` times a second (5 Hz by default), from full down by `depth` percent (50) and back. **Shape**: *Sine* (the default), *Triangle*, *Square* or *Saw*. See [below](#tremolo-and-vibrato). |
 | **Vibrato** | Makes the pitch swing `rate` times a second (5 Hz), `depth` semitones up and as far down (0.5). **Shape** as on the Tremolo; a *Square* jumps between two pitches. See [below](#tremolo-and-vibrato). |
@@ -853,6 +853,37 @@ Both (#326) work on the whole sound passing them: on a voice that is one sound,
     so the node keeps hearing.
   - The pictures of the tab, curve and levels, are not on the panel. A double-click on the node
     opens the tab for them.
+- **The Limiter's node is a device as well** (#397): a plate of brushed brick, 720x280 graph
+  units, its inputs on the left and its output on the right. It has no tab.
+  - **Chrome knobs**: threshold large, ceiling and release small beside it. They turn and reset
+    as the Compressor's do, each one undo step. A knob whose input is linked is greyed. At wet 0
+    the knobs and the lever are pale and the screen says `DRY`.
+  - **Auto-gain** is a lever at the top right. Beside it stands what it gives, `ceiling -
+    threshold`, for example `+5 dB`, or `off`.
+  - **The lamp** `LIMIT` beside the name lights red while the Limiter takes something away.
+  - **The screen** catches what the Limiter takes away **from the moment a sound starts**: the
+    reduction hangs down from the top, 0 to 24 dB by the square root like the Compressor's meter,
+    with marks at 1, 3, 6, 12 and 24 dB. Along the bottom runs the level coming in, -60 to 0 dB,
+    orange above the line of the limit. Time runs across from the start of the sound. The screen
+    shows 1 s and grows to 2, 4 and 8 s as the sound goes on. A longer sound rolls, and the last
+    8 s of it are kept. The times stay counted from its start.
+  - **It is held**: once nothing has come in for 0.4 s, the capture stands still, the silence
+    after the sound left off, until the next sound starts a new one. Above the screen stands
+    `WAITING FOR SOUND`, `LIVE` or `HELD`. Under it the most taken away is written with when, for
+    example `MOST -11.9 dB AT 0 ms`, and the time counts from the first reading that is heard.
+    On the right stands `NOW -3.9 dB` while live and `LASTED 1.47 s` once held. A white line
+    and dot mark the most. A capture is also held when the node leaves the picture.
+  - **How it is read**: from the same taps as the Compressor's, a gain of 1 in front of the node
+    and behind it. Each frame reads the loudest sample since the last frame, at least 25 ms, at
+    most 150 ms. The side in front is read 5 ms earlier, as late as the Limiter is, so a peak
+    going in is met by what it became. What is taken away is the level in less the level out,
+    without the auto-gain. Below 1, Wet blends the limited sound with what came in, and the
+    reading is solved for the limited part: `out / in = wet * gain * auto + (1 - wet)`. Less than
+    0.2 dB counts as none.
+  - **Measured** (2026-10-10, live, stein2): the seeded blip at -4.4 dBFS through a threshold of
+    -12 dB showed 7.56 dB taken away. A sound of three hits at 0, -8 and -2 dBFS showed
+    11.9 dB at the first and lasted 1.47 s on the screen (the file is 1.5 s, the first hit
+    50 ms in). In e2e 34 (test Chrome) -10.44 dBFS in against a limit of -20 dB showed 9.56 dB.
 - **Measured** (2026-10-07, e2e 34, Chrome offline): an impulse came out of the Compressor 288
   samples late and out of the Limiter 240. A 1 kHz sine at -18 dB through a hard-knee
   Compressor at -24 dB and 4:1 came out at -17.92 dB with auto-gain on and at -22.42 dB with it