docs: close out wave Theta-W4, and defer the deck layout rework to TODO

docs/TODO.md

@@ -179,3 +179,48 @@ Forward-looking follow-ups. Deferred by decision, not oversight — each entry r
 **Priority / risk.** Low / deferred. Mitigated in the meantime: the console message names the stranded file's project-relative path, so the operator can recover or remove it rather than discovering it later as an unexplained orphan.
 
 **Done looks like.** Switching projects mid-record leaves the recorded file with a ledger record in the project it belongs to, so a later prune of that project can reclaim it normally.
+
+## The deck layout needs a real rework — one row, taller decks, controls stacked within a deck
+
+**Context (what shipped — Θ-W4-T2).** The VELOCITY deck group landed with the amp, pitch,
+and filter velocity-curve buttons together, but the group placement lands wherever the
+existing per-row deck layout happens to put it. Daniel does not want multiple rows of
+decks. He wants **one row**, with the decks **much taller** to accommodate the controls —
+knobs stacked *within* a deck rather than strung out in a long line of small knobs. His
+example: the filter's static control knobs go **above** the filter envelope knobs.
+**He has further design notes coming**, so this is not ready to implement — it is
+recorded here so it is not lost and not attempted piecemeal.
+
+**The wart.** Θ-W4-T2's acceptance criterion "VELOCITY sits immediately to the left of
+the VOICE group" is **not met at the default window size**. This is **superseded by the
+deferred rework**, not silently dropped — recorded here so a later reader does not see an
+unmet criterion with no explanation.
+
+**Intended fix.** Not yet specified beyond the shape above (one row, taller decks,
+within-deck knob stacking) — Daniel's further design notes are still to come.
+
+**The constraint the fix MUST handle.** Not yet known — this is exactly why the rework is
+deferred rather than attempted against the current spec.
+
+**The measured geometry — the data the rework starts from.** Measured at the 840 px
+floor window, `availWidth = 824`, Gate mode. Group widths: PITCH 150, PITCH ENV 204,
+FILTER 440, FILTER ENV 252, AMP 252, VELOCITY 156, VOICE 152, MASTER 60. Row 1 = PITCH +
+PITCH ENV + FILTER (818 of 824). Row 2 = FILTER ENV + AMP + VELOCITY (684). Row 3 = VOICE
++ MASTER (224). Deck height 280 px; waveform band 246 px against a 150 px two-lane floor,
+so 96 px of margin. No reordering can fit two rows — 1666 px of groups plus 72 px of gaps
+against a 1648 px two-row capacity. Two rows first fit at a 936 px window.
+
+**Unresolved measurement discrepancy.** The VELOCITY↔VOICE adjacency threshold was
+measured at a 864 px window by the implementation and stated as 872 px by code review;
+the implementation flagged the difference rather than asserting the reviewer wrong, and
+it was not re-measured because the deferral made it moot.
+
+**Priority / risk.** Deliberate deferral, not oversight. Daniel wants to finish his
+design notes before this is attempted, to avoid building a layout that gets reworked
+piecemeal.
+
+**Done looks like.** One row of decks, each much taller than today's, with each deck's
+controls stacked internally (e.g. the filter's static control knobs above its envelope
+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.