Give every sound FX effect a Bypass and a Wet (#354)

A node could only be taken out of a sound FX by unplugging it, and
only six of them could be blended with the sound they get. Every
effect now has both, in the sound FX graph and in the instrument
graph alike. The Mix, the Input and the Output have neither.

- Bypass is a checkbox setting. A bypassed node is left out when
  the graph is compiled, so it costs nothing and holds nothing back.
  The graph draws it faded, and its body says "Bypass: true".
- Wet is a number input like the others. It can be a parameter, be
  moved by Set sound FX parameters and, where the node allows it for
  its other numbers, follow an Envelope.
- A blend is a stage of its own (`wet`) around what the node adds.
  The sound as it came in is held back as far as the node is late,
  so a Compressor, a Limiter or a Vibrato do not comb it out.
- The six nodes that had a Mix keep their key `mix` and only call
  it Wet. Saved values, parameters and edges stay as they were.
- The Delay crossfades now: the sound alone at 0, the sound and its
  echoes in full at 0.5, the echoes alone at 1. Before, the sound
  was always in full and `mix` was the echoes.
- The Pitch takes its semitones by Wet instead of blending, through
  a share `times` on the amount that an instrument binds as well.

Findings:

- A Delay saved before this sounds different. It sounds the same at
  half its old value. The two chip presets with a Delay (Echo Lead,
  Bell) are halved to keep their sound.
- Project cbbf160bb7e8 has two Delays (mix 1 and 0.5). They are
  left as they are.

Tests:

- Unit: soundfx 65 (8 new), sound-library 107 (3 new), instrument
  35 (1 new), envelope 13. Two delay tests and the filter ports test
  follow the new numbers.
- Counter-checks: 8, each turns its test red.
- e2e 34 (melektaus-atx): ALL PASSED, 83 checks (2 new). The
  ping-pong check at wet 0.25 measures what it did at mix 0.5.
- Gate (melektaus-atx): CHECK EXIT 0, 268 files, 4154 tests.
- After the gate the derived ports of a blend are asked for once
  instead of twice: typecheck, lint and the three unit files green
  again (113 tests).

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

src/editor/debug/graphHooks.ts

@@ -101,6 +101,8 @@ export function graphHooks({ state, editor }: HookContext) {
       info: () => editor.soundFxEditor.shownInfo,
       canvasRect: () => editor.soundFxEditor.canvas.canvasRect(),
       nodeProblem: (nodeId: string) => editor.soundFxEditor.canvas.nodeProblem(nodeId),
+      nodeSettings: (nodeId: string) => editor.soundFxEditor.canvas.nodeSettings(nodeId),
+      nodeAlpha: (nodeId: string) => editor.soundFxEditor.canvas.nodeAlpha(nodeId),
       /** The header's listening controls: which sound, and whether Play is offered. */
       preview: () => ({
         sound: editor.soundFxEditor.previewSoundId,