chore: upgrade express-rate-limit 7.5.1 → 8.3.1 (IPv6 security fix)

- Fixes IPv6 rate limit bypass vulnerability (GHSA-46wh-pxpv-q5gq)
- IPv6 addresses now masked to /56 subnet by default
- Updated custom keyGenerators to use ipKeyGenerator() helper
- 5 new TDD tests for v8 features (ipKeyGenerator, IPv6 masking)
- 672 tests passing, 0 TS errors, 0 npm audit vulnerabilities

package-lock.json

@@ -10,7 +10,7 @@
       "dependencies": {
         "compression": "^1.8.1",
         "express": "^5.1.0",
-        "express-rate-limit": "^7.5.1",
+        "express-rate-limit": "^8.3.1",
         "helmet": "^8.1.0",
         "marked": "^17.0.4",
         "nanoid": "^5.1.6",
@@ -2339,10 +2339,13 @@
       }
     },
     "node_modules/express-rate-limit": {
-      "version": "7.5.1",
-      "resolved": "https://registry.npmjs.org/express-rate-limit/-/express-rate-limit-7.5.1.tgz",
-      "integrity": "sha512-7iN8iPMDzOMHPUYllBEsQdWVB6fPDMPqwjBaFrgr4Jgr/+okjvzAy+UHlYYL/Vs0OsOrMkwS6PJDkFlJwoxUnw==",
+      "version": "8.3.1",
+      "resolved": "https://registry.npmjs.org/express-rate-limit/-/express-rate-limit-8.3.1.tgz",
+      "integrity": "sha512-D1dKN+cmyPWuvB+G2SREQDzPY1agpBIcTa9sJxOPMCNeH3gwzhqJRDWCXW3gg0y//+LQ/8j52JbMROWyrKdMdw==",
       "license": "MIT",
+      "dependencies": {
+        "ip-address": "10.1.0"
+      },
       "engines": {
         "node": ">= 16"
       },