docs(product): system-wide visual design language (S0-DS kit + S14 panel refresh)

LICE verified sufficient from vendored WDL — current editor draws at its
floor (flat fills, raw GDI text); no framework shift needed, D-A holds.
Adds design-language doc (palette, three directions, motion policy),
S0-DS shared drawing kit before S10, S14 panel refresh.

CONTEXT.md

@@ -1392,6 +1392,83 @@ without re-opening each editor. The missing trigger: a **bank-generation counter
 This seam serves **both** S8 ingest and M10 recapture; the writer side is extension-only and
 independent of S8, so it can land alongside either.
 
+## Design-system foundation (S0-DS + S14; "the VST is dogshit / temple os", 2026-07-26)
+
+**The diagnosis, from the vendored source, not lore.** Daniel DAW-tested the instrument and
+called the look "temple os … the VST is dogshit," and asked whether Cockos ships a toolkit for
+this. It does, and it's already vendored — the problem is the current editor draws at the
+**floor** of it. The S1–S6 editor renders flat opaque `LICE_FillRect` blocks and pipes text
+through raw GDI **`DrawTextA`** (reasampler_editor.cpp) — no gradients, no anti-aliasing, no
+rounded corners, no hover, aliased system text. That is the entire "temple os" look. The
+toolkit ceiling is not the constraint.
+
+**The toolkit (verified against `vendor/WDL`).** Two layers, both in hand:
+- **LICE** (`vendor/WDL/WDL/lice/`) — Cockos's 2D rasterizer, the same one REAPER's themed UI
+  and SWS draw with. Verified surface beyond the flat `LICE_FillRect` the editor limits itself
+  to: `LICE_GradRect` (gradient fills), `LICE_Line`/`LICE_FLine`/`LICE_ThickFLine` (AA lines,
+  `aa=true` default), `LICE_RoundRect` (AA rounded rects), `LICE_Circle`/`LICE_FillCircle` (AA),
+  `LICE_DrawCBezier` (AA curves — envelope draw), `LICE_FillTriangle`/`FillTrapezoid`/
+  `FillConvexPolygon`, per-primitive `alpha`+blend `mode`, and a real font engine
+  `LICE_CachedFont`/`LICE_IFont` (`lice_text.h`: AA glyph cache from an `HFONT`, `SetTextColor`,
+  `DrawText`, and shadow/outline/glow FX flags). **This is a sufficient modern-dark-UI toolkit
+  with no new dependency.**
+- **WDL VirtualWnd (vwnd)** (`vendor/WDL/WDL/wingui/virtwnd*.{h,cpp}`) — the retained-mode
+  LICE-drawn *widget* layer REAPER/SWS use: `virtwnd-iconbutton` (buttons), `virtwnd-slider`
+  (sliders + `vwnd_slider_drawknobstack` knobs), `virtwnd-listbox` (scroll lists),
+  `virtwnd-skin` (image skins), `WDL_STYLE_*` gradient/knob hooks. **Fork DS-1 settled A:
+  crib vwnd's drawing craft (read `virtwnd-slider.cpp` as the reference for a good LICE
+  slider/knob), do NOT adopt its object model** — its controls own their hit-test internally,
+  which would move geometry back into untestable shell code and undercut the pure/shell split
+  the codebase relies on. (Narrow build-time exception: vwnd's *listbox* for the S12 scroll
+  list only.) **iPlug/IPlug (VST2-era, dated — reject), iPlug2/JUCE (a framework shift that
+  re-opens settled D-A to solve a non-ceiling problem — reject), VSTGUI (the D-A fallback rung,
+  now moot since S1's LICE bridge landed).** Full toolkit assessment + palette + the three
+  visual directions + all forks: `docs/product/visual-design-language.md`.
+
+**S0-DS — shared LICE drawing kit (BEFORE S10).** One shared kit — palette + type + component
+draw — both the VST editor and the bank panel draw through, so "scope it for the whole system"
+is one source, not two divergent restyles. **Sequenced before S10** so the keyboard-strip
+editor is built in the new language, not restyled after. Honors the house split: the *geometry*
+(a role→color `theme` module — direction selectable via one constants block — and component
+layout/hit-test helpers) is **pure and CTest-covered** (mirror of `mode_switch`/`embed_strip`/
+`editor_geometry`); the *draw* (LICE `fillSurface` with micro-gradient + inner highlight,
+`drawButton`/`drawSlider`/`drawListRow`/`drawWaveform`/segment draw, and shared `LICE_CachedFont`
+text) is shell. The kit defines the **interaction state model** the current editor lacks
+entirely — rest / **hover** / active / pressed / dragging / focus / disabled — and the
+double-buffered zero-jank draw discipline (draw to `LICE_SysBitmap`, single `BitBlt`) already in
+both artifacts is preserved.
+
+**Palette + "punch" rule (Daniel's standing taste).** Dark, modern, **visual punch over
+conservative contrast**: for each text-on-surface pair, take the *most* vibrant accent that
+still clears its WCAG floor (AA 4.5:1 body / 3:1 large + state indicators) — the floor
+approached from the vibrant side, never a retreat to safe gray. Palette is defined by **role**
+(base/panel/cell/text-primary/text-dim/accent/accent-hot/warn), not hardcoded hue, so the visual
+direction (fork DS-2) is a single constants block. Surfaces gain a micro-gradient + 1px inner
+highlight/shadow (the vwnd trick) instead of flat fills; text moves to AA cached fonts (the
+single biggest "temple os → modern" lever).
+
+**"Speed is the selling point" — read as a design constraint, not a tagline.** The UI must
+*feel* instant: sub-frame hover/press/drag feedback repainted immediately on the input message
+(instant acknowledgment *is* the perception of speed); zero-jank via the preserved double-buffer;
+region-scoped `InvalidateRect` during a drag (build-time residual). **No decorative animation** —
+no tweens/fades/pulses; the only permitted motion is a level/meter readout following the audio
+directly (as the embed strip already does). Animation that costs a frame of latency violates the
+speed promise. The "fast" feeling is typography + hover + no-jank, not motion.
+
+**S14 — dock-panel refresh (extension-side, lighter).** The panel is "not terrible" — this is
+kit-application, not redesign (fork DS-3 settled light): route its text through the shared
+cached font (retire GDI text), re-draw buttons/tab-strip/segmented-switch/toggles through the
+kit, adopt palette roles + micro-gradient surfaces, add hover to tabs/rows. **Structure
+untouched** — the vertical-split / tab / grid layout and the pure `bank_grid`/`tab_strip`/
+`mode_switch` hit-test sources of truth stay exactly as landed; only draw upgrades.
+Extension-side, independent of the VST S10–S13 chain, parallelizable after the kit.
+
+**Sequencing:** `S0-DS` gates both S10 and S14. The prior "S10 leads the UX overhaul" becomes
+"**S0-DS leads, then S10**" — the kit is a small foundation, not a detour. Constraints all
+hold: **LICE/SWELL only** (D-A reinforced, not re-opened), **pure geometry modules** for all
+layout/hit-test, RT discipline untouched (draw-thread only), instrument stays a read-only bank
+consumer (a visual refresh is not a data-ownership or compat event — VST3 class UID unchanged).
+
 ## ReaSampler 9000 — the UX overhaul (S10–S13; DAW-tested S1–S6, "the UX is awful")
 
 **The bar is set: better than ReaSamplOMatic5000.** Daniel DAW-tested the S1–S6
@@ -1434,7 +1511,9 @@ read-only-over-bank stay settled.
   geometry module (key-span↔pixel reusing the `embed_strip` idiom; edge-grab vs. body-move
   hit regions; `pixel→note`; drag-delta resolver). Shell extends the click-only `wndProc`
   to a `WM_MOUSEMOVE`/`WM_LBUTTONUP` drag-state machine with live feedback, one coherent
-  edit on release.
+  edit on release. **Built in the S0-DS kit's language** (drawn through the shared component
+  kit, not the flat `LICE_FillRect`/GDI path); the drag machine's `WM_MOUSEMOVE` tracking
+  also lights the kit's hover states at near-zero marginal cost.
 - **S11 — waveform view + draggable loop points.** Selecting a zone shows its sample's
   **waveform** (peaks via the existing `peaks` module over the shell's already-decoded PCM
   — no new decode/WAV path) with draggable **start/end/loop-start/loop-end** markers that
@@ -1524,6 +1603,15 @@ Set by Daniel on DAW-testing the S1–S6 instrument, alongside the UX-overhaul d
 - **LICE/SWELL editor.** Reuses the `bank_panel` LICE/SWELL drawing surface; verify the
   `IPlugView`↔LICE window/bitmap bridge at the spike (window creation, sizing, event
   routing) — the least-trodden edge of the phase.
+- **LICE design-kit surfaces (S0-DS).** Verified *present* in `vendor/WDL/WDL/lice/lice.h` +
+  `lice_text.h`: `LICE_GradRect`, `LICE_RoundRect`, AA `LICE_Line`/`LICE_FLine`/
+  `LICE_ThickFLine`/`LICE_Circle`/`LICE_FillCircle`/`LICE_DrawCBezier`, `LICE_FillTriangle`/
+  `FillTrapezoid`/`FillConvexPolygon`, and the `LICE_CachedFont`/`LICE_IFont` font engine
+  (`SetFromHFont`, AA `DrawText`, shadow/outline/glow FX flags). **Verify exact signatures +
+  the `LICE_CachedFont`↔`HFONT` lifecycle before use.** vwnd reference (drawing craft only,
+  not the object model): `vendor/WDL/WDL/wingui/virtwnd-slider.cpp` /
+  `vwnd_slider_drawknobstack` for slider/knob rendering, `virtwnd-controls.h` for the
+  `WDL_STYLE_*` gradient hooks.
 
 ## Drop-and-load — drag a capture onto a track's FX button (S17 spec)