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/reply.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1024 1024"><path d="M415.937331 320 415.937331 96 20.001331 438.176C-6.718669 461.28-6.622669 498.784 20.033331 521.824L415.937331 864 415.937331 640C639.937331 640 847.937331 688 1023.937331 928 943.937331 480 607.937331 320 415.937331 320" p-id="4051" data-spm-anchor-id="a313x.7781069.0.i0"></path></svg>