feat(frontend): race form, start time selects, calendar views, day page

- Hide org schedule fields when editing a past race; isRaceDateInPast helper
- StartTimeSelects (HH:mm:ss) and optional ?date= prefill on new race
- Full-card link to edit for races needing result entry; shadow token
- List/calendar toggle (sessionStorage); year grid and month focus views
- Date hover popover and /races/day/:ymd page with Add button
- Docs plan-korrektirovok-starty.md and startTime API note; client 0.4.0

Made-with: Cursor

frontend/src/styles/tokens.css

@@ -27,4 +27,6 @@
   --radius-sm: 0.375rem;
   --radius-md: 0.75rem;
   --radius-lg: 1rem;
+
+  --shadow-card-lift: 0 6px 20px rgba(19, 32, 43, 0.12);
 }