Add full banner headers to all scripts across the codebase

Every script now has the established header format: PURPOSE with ─────── separator,
OPERATIONAL MODEL, DESIGN PRINCIPLES, OPERATIONAL SAFEGUARDS, CONFIGURATION, and
RUNTIME MODES — structured with full ====== banner sections throughout.

Orchestrators converted from compact ── inline format to full banners. Stale
emby-fallback and dirty sync references removed from Plugin/user_script_plug-in.sh.

Media/sonarr_tvdb_removed.sh

@@ -23,6 +23,25 @@
 # Per-deletion output is always visible — deletions are never silently swallowed.
 #
 # ==============================================================================================
+# DESIGN PRINCIPLES
+# ==============================================================================================
+#
+# Health Error Hygiene
+#   status="deleted" series can never be monitored or downloaded — they only
+#   generate persistent health errors. Removing them is maintenance, not
+#   data loss: most have no associated files.
+#
+# Conservative File Handling
+#   Files are not deleted by default. A TVDB-removed series may still have
+#   episodes on disk that the user wants to keep. The --delete-files flag
+#   is an explicit opt-in, not the default path.
+#
+# Exclusion List Prevents Re-add
+#   Removed entries are added to Sonarr's import exclusion list by default.
+#   Without this, the same deleted series can be re-added by lists or searches
+#   and immediately generate the same health error again.
+#
+# ==============================================================================================
 # OPERATIONAL SAFEGUARDS
 # ==============================================================================================
 #