Fix Emby auth header and arr cleanup pre-flight scan

Emby 4.9.5 rejects X-Api-Key — notify_emby_scan() now uses X-Emby-Token
consistently with emby_api(). Radarr v6 changed DownloadedMoviesScan to
require a path parameter — both cleanup scripts now use ProcessMonitoredDownloads
which achieves the same pre-flight intent without a path.

common.sh

@@ -1666,7 +1666,7 @@ notify_emby_scan() {
     # Get all scheduled tasks
     local tasks_response
     tasks_response=$(curl -sf --max-time 15 \
-        -H "X-Api-Key: $EMBY_API_KEY" \
+        -H "X-Emby-Token: $EMBY_API_KEY" \
         "${EMBY_URL}/ScheduledTasks" 2>/dev/null)
 
     if [[ -z "$tasks_response" ]]; then
@@ -1702,7 +1702,7 @@ notify_emby_scan() {
     local http_code
     http_code=$(curl -sf --max-time 15 \
         -X POST \
-        -H "X-Api-Key: $EMBY_API_KEY" \
+        -H "X-Emby-Token: $EMBY_API_KEY" \
         -w "%{http_code}" \
         -o /dev/null \
         "${EMBY_URL}/ScheduledTasks/Running/${task_id}" 2>/dev/null)