docs: record round 2 wayfinding concept, cuts and alternatives

docs/redesign/round2.md

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+# Round 2: Wayfinding
+
+## Concept
+
+The site is a night drive, so the reading layer should follow the rules of a road.
+Round 1 added effects around the drive (a boot terminal, a cursor headlight, a grain
+overlay, an operations ticker). Round 2 removes those effects and gives everything a
+single sign language. Every chapter is an **exit**, numbered the same way everywhere:
+
+- the 3D roadside sign that drives past (`EXIT 03`, then the next exit, an exit arrow),
+- the chapter panel (a chamfered `EXIT 03` tab on the top edge, plus `THEN → Infrastructure`),
+- the navigation gantry (leading-zero exit counters at wide widths),
+- the dash cluster (exit tab, route %, chapter, Bucharest local time),
+- project registration plates (`05.1 / PRIVATE / ACTIVE`) and lettered evidence stops (A–D).
+
+Each exit uses its chapter accent (rose, violet, cyan, coral) in both CSS and the sign
+texture, so the world and the page tell you the same thing at the same moment.
+
+## Changes
+
+- **Sign faces** (`src/scene/world/sign.ts`): redrawn as exit signs, with an accent tab, a
+  "THEN" line, a fitted label, a lane rule and a 45° exit arrow that mirrors for left-side
+  signs. The emissive edge takes the chapter accent. This also fixes a numbering defect:
+  signs used to say Profile = ROUTE 02 while the CSS numerals said 01.
+- **Exit plates** (`src/styles/wayfinding.css`, which replaces `nightshift.css`): all labels are
+  CSS generated content with empty alt text (`/ ''`), so the no-JS semantic document is
+  unchanged. On arrival the current chapter's tab flickers on once, like a neon tube
+  catching (this is gated behind reduced motion).
+- **Soundtrack coupling** (`src/audio/music-pulse.ts`): an analyser tap on the mixer output
+  reads the low bins once per frame inside the existing scene loop. While audio is running
+  and audible, kicks push the terrain surge and the sun bloom. When audio is muted or off
+  it reads 0 and adds no work.
+- **Mask win** (`sign-stage.ts`): the opening reading-mask reveal is quantized to 24 steps,
+  so the mask-image string, and the repaint it triggers, changes at most 24 times instead
+  of every scroll frame.
+- **Hero scrim**: its bottom is feathered with a static mask, which removes the dark band
+  that showed while scrolling.
+- **Vignette**: plain alpha with no blend mode, so it is never re-blended against the canvas.
+
+## Cut from round 1
+
+- `useHeadlight` (the beam and spotlight): a pointer-follow effect that cost work on every frame.
+- `BootSequence`: a terminal-log cliché that delayed the hero.
+- `OperationsStrip`: a third bottom pill. Its clock moved into the dash cluster, and uptime was dropped.
+- The soft-light grain overlay over the canvas, which cost compositing on every frame.
+- The hover font-weight change on the hero name, which caused layout work.
+
+## Alternatives considered
+
+- **Editorial dossier** case studies with sticky media columns. This is blocked because the
+  live reading stage translates `.portfolio-main`, so `position: sticky` does not work inside it.
+- **Grain or film post pass** in the WebGL composer. Rejected for its fill-rate cost on low tiers.
+- **Physical sign assets from Blender**. Deferred, because the signs are procedural
+  geometry with canvas faces, so the redesign needed no GLB changes and kept the first-scene budget.
+- **Per-chapter sky events** (meteors, a city skyline on approach). Worth doing, but it is scene work
+  that needs its own performance pass.