Split Event Manager's race-mode page into tabs

The race-mode management page (participants, teams, race format,
live grid/standings, and now the schedule/print tools) had grown into
a long scroll. Grouped into four tabs - Participants & teams, Format,
Live & results, Schedule & print - matching the tab pattern already
used for Settings. Only wrapper divs were added; no section's markup
or event bindings moved. The existing step-card overview and warning
links now switch to the right tab before jumping to it, and Open Grid
switches to the Live tab so its target is actually visible. Track/
sponsor events, which never had this length problem, are unaffected.

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rc-racecore",
-  "version": "1.16.1",
+  "version": "1.17.0",
   "private": true,
   "description": "RC RaceCore live timing and race control with AMMC ingest and SQLite persistence",
   "engines": {