Add Lucide icon picker to the definition edit sheet

Ship a curated 36-glyph household subset via named lucide-react imports
(bundled, no CDN), offer it as a grid picker in the edit sheet, send the
chosen icon in create and edit bodies, and render it on the list row
with a generic fallback for no icon or an unknown legacy value.

Task b50b048f-40f6-418e-b571-ef6be3796296

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

admin/package-lock.json

@@ -8,6 +8,7 @@
       "name": "nestquest-admin",
       "version": "0.0.0",
       "dependencies": {
+        "lucide-react": "^1.47.0",
         "react": "^19.2.0",
         "react-dom": "^19.2.0"
       },
@@ -2257,6 +2258,15 @@
         "yallist": "^3.0.2"
       }
     },
+    "node_modules/lucide-react": {
+      "version": "1.47.0",
+      "resolved": "https://registry.npmjs.org/lucide-react/-/lucide-react-1.47.0.tgz",
+      "integrity": "sha512-o8C23aXpNQypRY73W7fW02EyvWJinEMXgKeGjFoKym0zj3Q73hD97A1IQps1g8C14HTGsOpZL0Am+xjfgFZAbg==",
+      "license": "ISC",
+      "peerDependencies": {
+        "react": "^16.5.1 || ^17.0.0 || ^18.0.0 || ^19.0.0"
+      }
+    },
     "node_modules/lz-string": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/lz-string/-/lz-string-1.5.0.tgz",