docs(phase-15): record polish round 2; mark slider decision superseded

Note the five round-2 changes in COMPLETED.md; mark §8 + the §2/§11 slider references superseded (scroll reverted to RadialKnob).

product-notes/phase-15-visualizer-controls-enhancements.md

@@ -76,7 +76,7 @@ change; the centering and chrome are the polish around it.
 - A deterministic three-row layout with conditional visibility (§3).
 - Re-primitiving the popover host to a **screen-centered, tinted modal** overlay (§4).
 - NowPlayingCard-matched panel chrome (§5).
-- One control changes widget type: **scroll/zoom becomes a slider, not a knob** (§3, §8).
+- One control changes widget type: **scroll/zoom becomes a slider, not a knob** (§3, §8). *(superseded 2026-06-17 — reverted to a RadialKnob; see §8)*
 - Per-control playful tooltips (§7) and the icon-colour change to light (§9).
 
 **Out of scope / unchanged.**
@@ -334,6 +334,10 @@ don't collapse one into the other.
 
 ## 8. The one widget-type change: scroll/zoom → slider
 
+> **SUPERSEDED (2026-06-17) — polish round 2.** Daniel reversed this decision after the initial landing:
+> the WAVE-row scroll/zoom control was reverted from `MudSlider` back to a `RadialKnob`. The scroll
+> control is now a knob like the other dials. The rationale below is the historical design record.
+
 Today all eight controls are `RadialKnob`s. Daniel wants the WAVE-row scroll/zoom to be a **slider, not a
 knob.** Use `MudSlider` (already in the codebase — `VolumeZone`, `WaveformSeeker` use it). Bind
 `Value`/`ValueChanged` to `ScrollSpeed` through the same `OnScrollSpeedChanged` → `NotifyChanged()` handler
@@ -403,7 +407,7 @@ Phase-12, this is moot; if it survives, align it to light too for consistency. F
    far-right of row 1 and does not reflow when collisions hides; both-off leaves toggles + color only.
 5. **Chrome:** panel has square corners, lighter-navy ground, thin light border — visibly matching
    NowPlayingCard's treatment. All colours token-sourced; no new hardcoded hex.
-6. **Widget types:** scroll/zoom is a slider bound to `ScrollSpeed` alone; the other seven continuous
+6. **Widget types:** scroll/zoom is a slider bound to `ScrollSpeed` alone *(superseded 2026-06-17 — reverted to a RadialKnob; see §8)*; the other seven continuous
    controls are knobs; lava/waveform are **iconographic lamp toggles** (lit/unlit).
 7. **Colour principle (green = interactive, light = non-interactive):** knob caption icons render **light**;
    "LAVA:" / "WAVE:" section labels render **light**; knob arcs/pointers, the scroll slider, and the lamp