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.

System_Essentials/conf_cache_save.sh

@@ -16,6 +16,28 @@
 #
 # Only partner confs are saved — own conf is always on disk.
 # Path adapts to storage mode: $SCRIPTS_DIR/.cache/vv/d (internal or appdata).
+#
+# ==============================================================================================
+# DESIGN PRINCIPLES
+# ==============================================================================================
+#
+# Save at Shutdown, Not at Boot
+#   The backup is created at array stop while the RAM cache is at its freshest.
+#   By the next boot the partner may be unreachable — but the conf is already
+#   preserved and available the moment conf_cache_restore.sh runs.
+#
+# Partner Only
+#   Own conf is on disk — always present, never needs saving. Only partner confs
+#   live in RAM and can be missing at the next boot.
+#
+# ==============================================================================================
+# OPERATIONAL SAFEGUARDS
+# ==============================================================================================
+#
+#   require_partnership — exits early if PARTNERSHIP_ENABLED=false
+#   detect_hosts()      — determines which confs to save (partner confs only)
+#   No-cache guard      — exits cleanly if RAM cache is empty or missing
+#
 # ==============================================================================================
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"