feat(icons): split built-in sprite into per-icon SVG sources and add ticket icon

Move the 114 built-in sprite icons out of assets/js/runtime/svg-icon.js into
assets/icons/sprite/{key}.svg and generate svg-icon.js with
tools/build-svg-sprite.mjs. Add ticket-color and use it for the user center
ticket entry. Update sidebar contract tests for the creator card labels.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/icons/sprite/hot.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1024 1024"><path d="M429.568429 1023.994675S87.04221 973.306939 87.04221 681.468456c0-291.838482 447.485673-319.486339 348.670187-681.468456 0 0 335.358256 104.959454 253.438682 431.613756 0 0 44.543768-28.159854 78.335592-83.455566 0 0 169.471119 131.071318 169.471119 330.75028 0 199.678962-235.006778 346.1102-346.622197 345.086205 0 0 120.319374-162.303156 10.751944-267.26261-155.135193-148.479228-89.087537-244.22273-89.087537-244.22273S133.633968 697.852371 429.568429 1023.994675"></path></svg>