fix: case-insensitive dead-vehicle matching on website

Spectra sends kills with uppercase roman numerals (V/VI) but player
lineup CDKs use lowercase (v/vi). Normalize to lowercase in
deadVehicleKey, logVehicle, and logLookups so dead-vehicle fading
works on the website event log.

frontend/src/App.jsx

@@ -4529,7 +4529,7 @@ function formatLogTime(ms) {
 }
 
 function deadVehicleKey(uid, cdk) {
-  return `${String(uid || '').trim()}:${String(cdk || '').trim()}`
+  return `${String(uid || '').trim()}:${String(cdk || '').trim().toLowerCase()}`
 }
 
 function deadVehicleKeysFromEventLog(eventLog) {
@@ -4552,7 +4552,7 @@ function logLookups(participants) {
         ; (participant.players || []).forEach((player) => {
           const vehicles = new Map()
             ; (player.vehicles || []).forEach((vehicle) => {
-              vehicles.set(String(vehicle.cdk || ''), vehicle.name || vehicle.cdk || 'Unknown')
+              vehicles.set(String(vehicle.cdk || '').toLowerCase(), vehicle.name || vehicle.cdk || 'Unknown')
             })
           players.set(String(player.uid), {
             name: player.nick || player.uid,
@@ -4596,7 +4596,7 @@ function logPlayer(players, uid) {
 
 function logVehicle(player, cdk) {
   if (!cdk) return 'Unknown'
-  return player.vehicles.get(String(cdk)) || String(cdk)
+  return player.vehicles.get(String(cdk).toLowerCase()) || String(cdk)
 }
 
 function structuredBattleEvents(eventLog) {