Migrate UI to Lucide icons, reorder sidebar, and polish journal/groups UX

- Replace emoji icons with Lucide across admin pages; add vendor/lucide.min.js and renderIcons() helper\n- Reorder sidebar logically (Dashboard, Journal, Students, Groups, Files, Links, Trash + admin sections)\n- Groups: open photo chronology only via the Фото button; covers no longer clickable\n- Journal: show group badge over card photo, compact AI-status icon beside description, and date range in empty-state message\n- Update README (AI worker, Lucide, worker.js)

package-lock.json

@@ -13,6 +13,7 @@
         "express-rate-limit": "^8.7.0",
         "heic-convert": "^2.1.0",
         "helmet": "^8.3.0",
+        "lucide": "^1.44.0",
         "multer": "^1.4.5-lts.1",
         "pg": "^8.13.0",
         "tar": "^7.4.3"
@@ -1018,6 +1019,12 @@
         "node": ">=8.0.0"
       }
     },
+    "node_modules/lucide": {
+      "version": "1.44.0",
+      "resolved": "https://registry.npmjs.org/lucide/-/lucide-1.44.0.tgz",
+      "integrity": "sha512-d30uv1R6AOLBddzVMeeSk6aDAhobqh7nFxMsXuWHyhMmxKRhpLivikbfkmgzbWsn8WTLQIceGMlFY4g3gn4reg==",
+      "license": "ISC"
+    },
     "node_modules/make-dir": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/make-dir/-/make-dir-3.1.0.tgz",