feat: add fill+border dual-color nodes, radial layout, and dark labels

Node fill color now encodes subscription status (paid/trial active/expired),
while border color indicates referral role (partner/top/active referrer).
Added BFS-based radial initial positioning to spread referral branches outward.
Updated legend with two sections and adjusted FA2 gravity for less clustering.

package-lock.json

@@ -23,6 +23,7 @@
         "@radix-ui/react-tabs": "^1.1.13",
         "@radix-ui/react-tooltip": "^1.2.8",
         "@radix-ui/react-visually-hidden": "^1.2.4",
+        "@sigma/node-border": "^3.0.0",
         "@tanstack/react-query": "^5.8.0",
         "@tanstack/react-table": "^8.21.3",
         "@telegram-apps/sdk-react": "^3.3.9",
@@ -2643,6 +2644,15 @@
         "win32"
       ]
     },
+    "node_modules/@sigma/node-border": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@sigma/node-border/-/node-border-3.0.0.tgz",
+      "integrity": "sha512-mE3zUfjvJVuAMhSjiP/zdlkqe0OVTETxd04XHUwof01YqdzTk0OB4ACJIhWrwgsBXl7tTd9lPuKoroafLh8MtQ==",
+      "license": "MIT",
+      "peerDependencies": {
+        "sigma": ">=3.0.0-beta.17"
+      }
+    },
     "node_modules/@standard-schema/spec": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/@standard-schema/spec/-/spec-1.1.0.tgz",