Add permanent browser tests for the Settings tabs, Event Manager tabs, and Schedule panel

These three UIs (all shipped earlier this session) had only been verified with throwaway
scratch scripts during development. Adds tests/browser_settings_tabs.js,
browser_event_manager_tabs.js and browser_event_schedule.js, wired into the existing
test:browser suite.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "rc-racecore",
-  "version": "1.17.1",
+  "version": "1.17.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "rc-racecore",
-      "version": "1.17.1",
+      "version": "1.17.2",
       "hasInstallScript": true,
       "dependencies": {
         "better-sqlite3": "^12.11.1",