Select Color: search boxes, readable icon buttons, cleaner Document and Color books layout

- Info line shows a colour-book colour as "BOOK - NAME".
- Document tab: a search box (by name) replaces the "Colors in this
  drawing" heading; grid swatches no longer carry text; larger grid/list
  icons, dark on the accent colour when active, like the OK button.
- Color books tab: no "Color book"/"Find" labels; the book list is as
  wide as the colour bars, and the search box (magnifier, gray "Search")
  and load button sit over the page strip and RGB values, all 28 px high;
  the load button and page arrows use the button's dark text colour.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_013rGmDUNr1hUf4zo1X3dak8

assets/icons/ui/search.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#B4B6B9" stroke-width="2" stroke-linecap="round"><circle cx="10.5" cy="10.5" r="6"/><path d="M15 15l5 5"/></svg>