Add RAG retrieval core, and correct six stale default values in headers

Chunker splits on the header sections the audit standardised, then sub-splits
named-paragraph safeguards — without that a specific question about one of
rsync.sh's fourteen safeguards scored below unrelated chunks, because the other
thirteen dominated the vector. Index is SQLite with raw float32 blobs and is
incremental on mtime; a no-op re-index takes 66ms.

The stale defaults were found by asking the system a question and checking its
answer: it correctly reported what mover_stop.sh's header claimed, and the
header was wrong.

Plugin/unraid/System_Essentials/mover_stop.sh

@@ -74,7 +74,7 @@
 # master.conf
 #
 #   MOVER_STOP_TIMEOUT
-#       Seconds between wall warning and SIGTERM. (default: 30)
+#       Seconds between wall warning and SIGTERM. (shipped default: 300)
 #
 # ==============================================================================================
 # RUNTIME MODES