feat(quench): add Quench sub-safe clipper

Quench splits the signal with a Linkwitz-Riley crossover and lets the sub
pass unclipped. The top is clipped symmetrically at the ceiling minus the
sub's held peak, so it does not pump at the sub's rate and the sum stays
under the ceiling. What the clip removes is high-passed at the split, so its
products stay out of the low band. Two correction passes and an oversampled
hard clip hold the ceiling; a safety clip catches the downsampler's ringing.

- Controls: Drive, Ceiling, Split, Hold, Soft, Bypass.
- Listen to Quench, a plain clipper at the same settings, or the delta.
- Editor meter compares how much the low band changed for Quench and for a
  plain clip, with a scope of the output, the sub and the top's room.
- Measured: sub level +0.04 dB against -2.2 dB for a plain clip, low-band
  products -35 dB against -16 dB, at 0.5-1.2 dB less RMS.
- Registered in the catalog, workflows, editor-check, README, chain and
  development docs, and the website copy.

docs/development.md

@@ -25,7 +25,7 @@ Patina has `render` for offline WAV evaluation. The shared crates are:
 
 - `common-ui`: palette, embedded fonts, header, panels, knobs, meters.
 - `common-dsp`: filters, YIN pitch tracking, the note tracker used by Anvil,
-  Lathe, Temper, Knurl, Planish and Braze, 4× oversampling, meters and WAV files.
+  Lathe, Temper, Knurl, Planish and Braze, 4× oversampling (also Quench's), meters and WAV files.
 
 The wrappers stay separate workspaces, each with its own lockfile, so the
 NIH-plug Git dependency stays out of the root workspace. Host identities and
@@ -45,7 +45,7 @@ python3 -m unittest discover -s scripts/tests -v
 ```
 
 Products: `rivet`, `patina`, `anvil`, `crucible`, `lathe`, `temper`, `weld`,
-`knurl`, `planish`, `braze`.
+`knurl`, `planish`, `braze`, `quench`.
 
 `check-plugin.py` runs formatting, tests and clippy for one product's packages
 and its wrapper, without compiling the other products. Run it for every product
@@ -146,6 +146,7 @@ identify plugins by CLAP ID, so the vendor name does not affect saved projects.
 | Knurl | (new) | `io.narl.bass-foundry.knurl` |
 | Planish | (new) | `io.narl.bass-foundry.planish` |
 | Braze | (new) | `io.narl.bass-foundry.braze` |
+| Quench | (new) | `io.narl.bass-foundry.quench` |
 
 CLAP IDs use the form `io.narl.bass-foundry.<product>`. Builds tagged before
 this scheme used `io.storyboard.*` IDs; hosts treat the new IDs as different