Add a time-of-day race day schedule to Event Manager

Events can now be given a start time and a gap between sessions on a
new "Schedule" panel; every session's planned clock time cascades
automatically in running order (practice, qualifying, finals), and
once a session actually starts or finishes, everything after it
re-anchors to that real time - a late start or a session that ran
long (including any pause) pushes the rest of the day forward with
no manual reschedule step. The scheduled time now also shows on the
printed/PDF start lists.

Printable start lists and manually moving a driver to start last in
their own heat (for a mechanic-time request) already existed, so
this only builds the missing piece: the schedule itself.

Also fixes a real pre-existing bug in the same session-ordering logic
this feature relies on: getSessionSortWeight used `order[type] || 99`,
which silently treated open_practice's own weight of 0 as falsy and
sorted practice sessions dead last instead of first in print/PDF
output.

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rc-racecore",
-  "version": "1.15.0",
+  "version": "1.16.0",
   "private": true,
   "description": "RC RaceCore live timing and race control with AMMC ingest and SQLite persistence",
   "engines": {