feat(race-day): add warm-up transponder check before a heat

Race Day gets a 1-3 minute warm-up per heat with a green check per
driver when their transponder is seen, countdown announcements
(sv/en), quick transponder fix from the panel, and a start warning
that still allows starting when someone is missing.

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

rc-race-sound-pack/sound_manifest.json

@@ -47,6 +47,9 @@
       "race_1_minute": "Race starts in one minute.", "race_30_seconds": "Thirty seconds to start.", "race_10_seconds": "Ten seconds to start.",
       "drivers_ready": "Drivers, stand by.", "start_sequence": "Starting on the sound of the tone.", "false_start": "False start.", "restart_race": "Prepare to restart the race.",
       "staggered_release": "Car {tp}.",
+      "warmup_start": "Warm-up has started. {minutes} minutes.",
+      "warmup_1_minute": "One minute of warm-up remaining.",
+      "warmup_end": "Warm-up is over. Drivers to the grid.",
       "personal_best": "Personal best. {driverName}. {lapTime}.", "fastest_lap": "Fastest lap. {driverName}. {lapTime}.",
       "training_stable_pace": "{driverName}, good pace and consistent driving.",
       "track_record": "New track record. {driverName}. {lapTime}.", "new_leader": "New race leader. {driverName}.",
@@ -69,6 +72,9 @@
       "race_1_minute": "Start om en minut.", "race_30_seconds": "Trettio sekunder till start.", "race_10_seconds": "Tio sekunder till start.",
       "drivers_ready": "Förare, gör er redo.", "start_sequence": "Start på signalen.", "false_start": "Felaktig start.", "restart_race": "Förbered omstart.",
       "staggered_release": "Bil {tp}.",
+      "warmup_start": "Uppvärmningen har startat. {minutes} minuter.",
+      "warmup_1_minute": "En minut kvar av uppvärmningen.",
+      "warmup_end": "Uppvärmningen är slut. Förarna till start.",
       "personal_best": "Personbästa. {driverName}. {lapTime}.", "fastest_lap": "Snabbaste varv. {driverName}. {lapTime}.",
       "training_stable_pace": "{driverName}, bra tempo och stabil körning.",
       "track_record": "Nytt banrekord. {driverName}. {lapTime}.", "new_leader": "Ny ledare. {driverName}.",