Restore @jsplumb/browser-ui dependency

Other parts of the product still rely on jsPlumb, so keep the dependency.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Claude

package.json

@@ -37,6 +37,7 @@
     "dev-data:status": "node scripts/dev-data-sync.mjs status"
   },
   "dependencies": {
+    "@jsplumb/browser-ui": "^6.2.10",
     "@lit/localize": "^0.12.1",
     "@open-wc/lit-helpers": "^0.7.0",
     "chart.js": "^4.4.8",

yarn.lock

@@ -1787,6 +1787,11 @@
     "@jridgewell/resolve-uri" "^3.1.0"
     "@jridgewell/sourcemap-codec" "^1.4.14"
 
+"@jsplumb/browser-ui@^6.2.10":
+  version "6.2.10"
+  resolved "https://registry.yarnpkg.com/@jsplumb/browser-ui/-/browser-ui-6.2.10.tgz#86b85ed42110563d2816e3712677cdbbbf33366f"
+  integrity sha512-trk++mK5q6hceJL79teemzcilJ+8DrZT/lMK0+B80AtHqZHr0YwMCf+so2JBb2Z/MDZ0fUEU9MbELY6OPhhs5g==
+
 "@kurkle/color@^0.3.0":
   version "0.3.4"
   resolved "https://registry.yarnpkg.com/@kurkle/color/-/color-0.3.4.tgz#4d4ff677e1609214fc71c580125ddddd86abcabf"