README: replace the title text with a DM Mono wordmark SVG (#17)

Add docs/assets/wordmark.svg and wordmark-dark.svg: "layeris" set in
DM Mono Regular (400) at 46px with -0.03em letter-spacing, matching the
docs site's .wordmark, with the glyphs converted to outlines. The two
files differ only in fill (the site's light and dark --ink colors).

The README title now shows the wordmark through a <picture> element so
GitHub picks the dark variant in dark mode.


Claude-Session: https://claude.ai/code/session_01UPUkrGnMDAicigzqmP8keN

Co-authored-by: Claude <noreply@anthropic.com>

Author: subwaymatch

README.md

@@ -2,7 +2,12 @@
 <img src="https://raw.githubusercontent.com/subwaymatch/layer-is-python/main/docs/assets/logo.svg" alt="Layer.is logo">
 </p>
 
-# Layer.is
+<h1>
+<picture>
+<source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/subwaymatch/layer-is-python/main/docs/assets/wordmark-dark.svg">
+<img src="https://raw.githubusercontent.com/subwaymatch/layer-is-python/main/docs/assets/wordmark.svg" alt="layeris" width="177" height="43">
+</picture>
+</h1>
 
 A library that supports all blend modes in Photoshop, brightness, contrast, hue, saturation, lightness adjustments, and curve adjustments on separate RGB channels.