fix(#377): add pnpm overrides for matrix-bot-sdk transitive vulnerabilities

matrix-bot-sdk depends on the deprecated `request` library which pulls
in vulnerable form-data (<2.5.4, critical: unsafe random boundary) and
qs (<6.14.1, high: DoS via memory exhaustion). Add pnpm overrides to
force patched versions since matrix-bot-sdk has no newer release.

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

package.json

@@ -57,8 +57,10 @@
   "pnpm": {
     "overrides": {
       "@isaacs/brace-expansion": ">=5.0.1",
+      "form-data": ">=2.5.4",
       "lodash": ">=4.17.23",
       "lodash-es": ">=4.17.23",
+      "qs": ">=6.14.1",
       "undici": ">=6.23.0"
     }
   }