Add a feedback for every controllable state, matrix send presets

A matrix-send knob looked dead on the booth Companion although the console
followed it (verified through Companion's rotate API: -90 -> -60 -> -59):
the module had matrix send actions but no matrix send feedbacks.

- Every action with a readable state now has a matching feedback: matrix
  send on/level text/level bar, matrix and control group solo and fader
  bars, graphic EQ in and band gain text/bar, aux send pan text, and value
  text for trim, gain and filter frequencies. A test checks the parity.
- New action: matrix output solo.
- Matrix sends use the console's -90 dB floor: adjusting down from -inf no
  longer writes -150 there.
- Presets: "Matrix sends to <output>" (on/off and knob per matrix input)
  and graphic EQ in/out. 2970 presets, 1.8 MB.

npm test: 368 checks pass on Node 25 and on Companion's Node 22.

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

companion/HELP.md

@@ -75,8 +75,10 @@ fader, mute and solo are on the Aux_Outputs or Group_Outputs side that matches i
 ## Actions
 
 Level actions take dB (`-inf` at the bottom of the number field). Every level has a **set** and a
-relative **adjust** version for rotary encoders; adjusting from -inf lands at -60 dB on the first step up.
-Toggles read the current state first when it is not known yet.
+relative **adjust** version for rotary encoders. A relative step cannot start from -inf: from −∞ the first
+step up jumps to −60 dB. A matrix send has its floor at **-90 dB** (the console reports off matrix sends as -90, and
+the module never writes lower); faders and aux sends go down to -150 dB. Toggles read the current state first when it
+is not known yet.
 
 | Group | Actions |
 | --- | --- |
@@ -106,14 +108,26 @@ snapshot's list position (0 = the first); verify it once on your console before
 
 ## Feedbacks
 
-* Boolean (button colour): input muted / solo, aux send on, group assigned, buss muted /
-  solo, matrix muted, control group muted, snapshot is current, fader level above/below a threshold, send
-  level above/below, console link alive, relay has an iPad, every channel-strip switch above, and the meter
+Every action that changes something the console reports has a feedback for it: a boolean for every switch, a value
+(text for a button's local variable) and a bar for every level. The state a feedback needs (sends, matrix sends,
+graphic EQ bands, channel-strip values) is loaded the first time one is shown, and each button re-checks only when its
+own value changes.
+
+* Boolean (button colour): input muted / solo; aux send on; group assigned; buss muted / solo; matrix output muted /
+  solo; control group muted / solo; **matrix send on**; **graphic EQ in**; snapshot is current; fader level above/below
+  a threshold; aux send level above/below; console link alive; relay has an iPad; every channel-strip switch
+  (phantom, phase, pad, EQ in, compressor in, gate in, high-pass in, low-pass in, delay in, insert A/B in); and the meter
   feedbacks below.
-* Value (use with a preset's local variable to put live numbers in button text): input fader, input pan,
-  send level, send On/Off, buss / matrix / control group fader, current snapshot name, input meter value.
-* Advanced bars: input fader, aux send level and buss fader draw a horizontal bar along the bottom of the
-  button (-60 to +10 dB); the input meter draws a vertical bar at the right edge (green, amber, red).
+* Value (put live numbers in button text with a preset's local variable): input fader and pan; aux send level, On/Off
+  and pan; buss / matrix / control group fader; **matrix send level**; **graphic EQ band gain**; trim, analog gain and
+  filter frequency per input and buss (trim also per matrix output); current snapshot name; input meter value. Levels
+  read `-inf` at or below -90 dB.
+* Advanced bars: input fader, aux send level, buss / matrix output / control group fader, **matrix send level** (all
+  -60 to +10 dB) and **graphic EQ band gain** (-12 to +12 dB) draw a horizontal bar along the bottom of the button;
+  the input meter draws a vertical bar at the right edge (green, amber, red).
+
+Not covered by a feedback: free-form *Send raw OSC*, and *Set name* (the name is the variable `input_N_name`). There is
+no matrix-output solo action, only its feedback.
 
 ## Variables
 
@@ -135,12 +149,15 @@ Presets are named with the live entity names and rebuilt when names load.
 | Sends to *aux name* | One section per named aux buss: per input an **On/off** button (green when on, shows the level) and a **Level (knob)** (turn = send level, press = on/off, with a bar) |
 | Group *group name* | One section per named group buss: per input an **Assign** toggle, green when assigned |
 | Matrix, Control groups | Mute and fader knob per output / group |
+| Matrix sends to *output name* | One section per matrix output: per matrix input an **On/off** button (green when on; shows `Matrix In N` and the level) and a **Level (knob)** (turn = send level, press = on/off, with a bar) |
+| Graphic EQs | One **In/out** toggle per graphic EQ, green when in |
 | Snapshots | **Fire** per snapshot (green when current), next, previous, current (display) |
 | Input meters | Level, gate gain reduction and compressor gain reduction buttons per input |
 | Console | Reload, connection status, relay status |
 
 Busses and control groups with no name are unused slots and get no presets. If the preset list would exceed
-3000 entries or 4 MB, the per-input send level knobs are left out and a warning is logged.
+3000 entries or 4 MB, the per-input gate / compressor reduction meter presets are left out first, then the
+per-input aux send level knobs, and a warning is logged.
 
 ## Meters