feat: chat integration, tenant admin spec, backend chat service, miniprogram updates, DEMO moved to tmp, XCX-TEST removed, migrations & docs

tmp/DEMO-miniprogram/miniprogram/assets/icons/ball-black.svg

@@ -0,0 +1,18 @@
+<!-- 黑色台球 - 大号8 -->
+<svg width="48" height="48" viewBox="0 0 48 48" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <radialGradient id="ballGradient" cx="35%" cy="35%">
+      <stop offset="0%" style="stop-color:#3a3a3a;stop-opacity:1" />
+      <stop offset="70%" style="stop-color:#1f2937;stop-opacity:1" />
+      <stop offset="100%" style="stop-color:#0f0f0f;stop-opacity:1" />
+    </radialGradient>
+  </defs>
+  <!-- 球体 -->
+  <circle cx="24" cy="24" r="18" fill="url(#ballGradient)"/>
+  <!-- 高光 -->
+  <ellipse cx="18" cy="16" rx="6" ry="4" fill="white" opacity="0.3"/>
+  <!-- 白色圆圈 -->
+  <circle cx="24" cy="24" r="8" fill="white"/>
+  <!-- 数字8 -->
+  <text x="24" y="29" font-family="Arial, sans-serif" font-size="11" font-weight="bold" fill="#1f2937" text-anchor="middle">8</text>
+</svg>