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/add-ring.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1024 1024"><path d="M512 1024C229.229714 1024 0 794.770286 0 512S229.229714 0 512 0s512 229.229714 512 512-229.229714 512-512 512z m0-928C282.258286 96 96 282.258286 96 512S282.258286 928 512 928 928 741.741714 928 512 741.741714 96 512 96z m208.018286 463.981714h-160v160.036572a48.018286 48.018286 0 0 1-96.036572 0v-160.036572H303.981714a47.981714 47.981714 0 0 1 0-95.963428h160V304.018286a48.018286 48.018286 0 0 1 96.036572 0v160h160a47.981714 47.981714 0 0 1 0 95.963428z"></path></svg>