Add arr_corruption_scan.sh — sequential ffprobe-based corruption scan for Sonarr

Healarr does the same job but crashes on a Go concurrency bug (unsynchronized
map access) whenever multiple corruption events land close together — confirmed
via its own crash log, not fixable from our side. Processing one file at a time
here sidesteps the whole bug class instead of trying to work around it.

Delete + explicit EpisodeSearch rather than relying on Sonarr's own background
missing-search cycle, since that skips unmonitored episodes and this shouldn't.

Deployment/host.conf.template

@@ -457,6 +457,17 @@
         # ["/movies"]="/mnt/user/Movies"
     )
 
+# ━━━ Corruption Scan ━━━
+    # Container that has a working ffprobe binary AND mounts the same shares as the arrs'
+    # roots — check `docker inspect <container>` for its mounts before filling this in.
+    HOSTN_FFPROBE_CONTAINER=""
+    HOSTN_FFPROBE_BIN=""
+
+    declare -A HOSTN_FFPROBE_PATH_MAP=(
+        # ["/mnt/user/Tv_Shows"]="/ext-tv-shows"
+        # ["/mnt/user/Movies"]="/ext-movies"
+    )
+
 # ━━━ Arr Recovery Toggles ━━━
     HOSTN_LIDARR_RECOVERY=false
     HOSTN_SONARR_RECOVERY=true