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/radarr_cleanup.sh

@@ -31,6 +31,25 @@
 # Emby removes ghost entries immediately — no user-facing file-not-found errors.
 #
 # ==============================================================================================
+# DESIGN PRINCIPLES
+# ==============================================================================================
+#
+# API as Ground Truth
+#   What Radarr tracks is authoritative. Files not in the API response are
+#   orphans — Radarr has no record of them and they serve no purpose.
+#   The script never infers ownership from directory structure alone.
+#
+# Age Gate Before Deletion
+#   Files under RADARR_ORPHAN_AGE are left alone regardless of tracked status.
+#   Radarr's import pipeline writes files before registering them — acting
+#   immediately would delete files mid-import.
+#
+# Emby Cleanup Is Part of the Job
+#   Deleting a file without telling Emby leaves ghost entries that show as
+#   broken items. Triggering the Emby clean is not optional — it completes
+#   the deletion from the user's perspective.
+#
+# ==============================================================================================
 # OPERATIONAL SAFEGUARDS
 # ==============================================================================================
 #