Add true-vector dark logo and brand colour record

[jaywedgeworth22]

Traces the owner-supplied dark CodeCaps logo into a genuine SVG, plus a machine-readable record of its palette.

Why a trace rather than a redraw. The obvious model for this mark — two elliptical annuli with a rectangular bite — does not fit. The best-fit ellipse deviates from the actual outline by tens of pixels near the poles, which is what capped an earlier analytic reconstruction at 0.9553 IoU. Tracing the real contour is both simpler and provably faithful.

Pipeline.

1. Two-colour alpha unmix. Every pixel in the artwork is a blend of exactly two flat palette colours, so each pixel is scored against all six unordered pairs and the best fit is kept. Deciding per pixel is genuinely ambiguous at low coverage — one-eighth teal over background and one-eighth white over background are nearly the same colour, because teal and white lie close to the same ray from the background. Scoring each pair over a 5×5 patch resolves that with local context, and it recovered a clean antialiased ramp where a plain RGB projection had produced crosstalk.
2. Marching squares at the 0.5 coverage level yields ordered subpixel contours: teal 1 loop, red 1 loop, white 7 loops (the needle plus six dots).
3. Douglas-Peucker simplification at eps=0.1.

Verification. The SVG is rendered with headless Chrome at 1024×1024 and compared against the source raster:

colour	IoU
teal	0.9965
red	0.9964
white	0.9909
total	0.9959

Mean per-channel pixel difference is 0.244/255. The earlier analytic candidate was 0.9553.

The residual is a half-pixel rasteriser convention difference; a uniform +0.5/+0.5 offset is applied, after which the residual misalignment measures 0.01–0.03 px.

Contents.

• assets/brand/codecaps-logo-dark.svg — 13.5 KB, no embedded raster. Delete the first <rect> for a transparent-background variant.
• assets/brand/brand-colors.json — the exact flat palette: #222325, #4FD1C5, #FF6B6B, #FFFFFF, with the method and fidelity numbers recorded alongside.

Refs CC-168

[linear-code]

CC-168