chore: bump version to 2.4.0

Step 1 of the v2.4.0 release: the bump lands on v2/main before the
milestone merge, so v2/main is never left behind main afterwards.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013hzwzS8UvBsr4yZm7o7sev
Signed-off-by: cliffhall <cliff@futurescale.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@modelcontextprotocol/inspector",
-  "version": "2.3.0",
+  "version": "2.4.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@modelcontextprotocol/inspector",
-      "version": "2.3.0",
+      "version": "2.4.0",
       "hasInstallScript": true,
       "license": "MIT",
       "dependencies": {