feat(series): run each round from the series page

Step 3 becomes a rounds table: pick drivers inline (copy from the
previous round, add a late entry), set qualifying rounds/finals/max
cars per heat per round, see the status, and create qualifying and
finals from there. Qualifying heats are now split evenly so nobody
drives alone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "rc-racecore",
-  "version": "1.36.1",
+  "version": "1.37.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "rc-racecore",
-      "version": "1.36.1",
+      "version": "1.37.0",
       "hasInstallScript": true,
       "dependencies": {
         "better-sqlite3": "^12.11.1",