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/media_shares_permissions.sh

@@ -14,6 +14,24 @@
 # or unRAID environment resets after updates.
 #
 # ==============================================================================================
+# DESIGN PRINCIPLES
+# ==============================================================================================
+#
+# Daily Failsafe, Not Enforcer
+#   Wrong ownership is a symptom of something else — a misconfigured container,
+#   a manual copy, an rsync without --chown. This script corrects the symptom
+#   daily rather than hunting the root cause. A persistent high correction count
+#   is the signal to investigate the source.
+#
+# Runs First in the Window
+#   Arr cleanup scripts depend on correct ownership to rename and delete files.
+#   Permissions must be correct before cleanup runs — ordering is not optional.
+#
+# Separate Passes for Directories and Files
+#   Directories need execute permission for traversal; files do not. Applying
+#   the same mode to both is a common mistake this script avoids by design.
+#
+# ==============================================================================================
 # OPERATIONAL SAFEGUARDS
 # ==============================================================================================
 #