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>

CHANGELOG.md

@@ -8,6 +8,12 @@ The application version is maintained in `package.json` and displayed in the adm
 
 No changes recorded yet.
 
+## 1.17.0 - 2026-09-11
+
+### Changed
+
+- Event Manager's race-mode page (a long scroll of participants, teams, race format, live grid/standings, schedule and print/PDF tools) is now split into four tabs - Participants & teams, Format, Live & results, Schedule & print - so a specific section is a click away. The existing step-card overview and "fix this" warning links now switch to the right tab automatically before jumping to it. Track/sponsor events, which only ever had a handful of panels, keep the simple untabbed layout.
+
 ## 1.16.1 - 2026-09-10
 
 ### Fixed