docs: close out Θ-W6 and Phase Θ, and file two legibility-pass deferrals

docs/TODO.md

@@ -252,3 +252,60 @@ controls stacked internally (e.g. the filter's static control knobs above its en
 knobs) per Daniel's design notes once they land. The VELOCITY↔VOICE adjacency criterion
 is re-evaluated (or explicitly retired) against the new layout rather than the old
 per-row one.
+
+## The AA waveform stroke's cost on the docked bank panel's card thumbnails
+
+**Context (what shipped — Θ-W6-T1, legibility-and-antialiasing).** The antialiasing
+audit fixed the min/max waveform column plot by adding an AA `LICE_FLine` stroke across
+each column's extremes, on top of the existing fill (`draw_kit.cpp` `drawWaveform`).
+`drawWaveform` is shared by the editor's hero waveform lanes, the docked bank panel's
+card thumbnails, and the browse cards — the stroke lands on all three.
+
+**The wart.** Measured cost (Release, MSVC 14.44, real LICE, 24 stereo cards ×
+136 columns = 6528 columns): fill alone 0.070 ms per full-grid repaint, fill+stroke
+0.48 ms — the stroke adds ~0.41 ms, about 2.5% of a 60 Hz frame. At card-thumbnail
+scale the added smoothness is far less visible than on the editor's hero lanes, so the
+cost is paid on every repaint of every card for a benefit concentrated in one consumer.
+
+**Intended fix.** The identified cheap lever: skip the stroke below a card-sized box
+and keep it only on the editor's hero lanes.
+
+**The constraint the fix MUST handle.** Not done, because it is a product call about
+where the comb artifact — the min/max column plot's jagged outline — actually reads
+badly enough to matter, not a performance-forced decision (2.5% of a frame on
+hover/scroll/drag repaint, not a continuous cost, is not itself disqualifying).
+
+**Priority / risk.** Low. The measurement is a one-off scratchpad number
+(`docs/product/visual-design-language.md` §8), not a standing regression guard —
+re-measure before relying on it again.
+
+**Done looks like.** A size threshold (or explicit per-consumer flag) below which
+`drawWaveform` skips the AA stroke, with the panel/browse cards confirmed still
+readable and the editor's hero lanes unchanged.
+
+## High-DPI host scaling is unverified (distinct from the antialiasing audit)
+
+**Context (what shipped — Θ-W6-T1, legibility-and-antialiasing).** The antialiasing
+audit (item 13) confirmed every drawn surface renders smooth at 100% scale — the
+disposition table in `docs/product/visual-design-language.md` §8 is the record. That
+audit is about rasterization quality at the pixel level the plugin already draws at;
+it says nothing about what happens when a host scales the plugin window itself.
+
+**The wart.** Nothing in the instrument implements `IPlugViewContentScaleSupport`. A
+host that applies DPI scaling to the plugin window resamples the already-rasterized
+output rather than asking the plugin to redraw at the target resolution — every AA
+guarantee the audit just confirmed (and the piano-key uniform-width guarantee, §8.1)
+holds only at the client-pixel level the plugin itself draws, not above it.
+
+**Intended fix.** Not proposed. Implementing `IPlugViewContentScaleSupport` (or
+confirming the host compositor's resampling is acceptable without it) is the shape of
+a fix, not yet scoped.
+
+**The constraint the fix MUST handle.** Not yet known — no design work has started.
+
+**Priority / risk.** Not stated. Recorded as a gap, not a defect: no host behavior has
+been observed to be wrong, only unverified.
+
+**Done looks like.** Either `IPlugViewContentScaleSupport` is implemented and the
+AA/uniform-width guarantees are re-verified at a scaled client size, or a decision is
+recorded that host-side resampling of the rasterized output is an accepted tradeoff.