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.

Rsync/rsync.sh

@@ -161,14 +161,14 @@
 #       Default retry attempts on rsync failure. (default: 3)
 #
 #   SLEEP
-#       Default seconds between retry attempts. (default: 60)
+#       Default seconds between retry attempts. (shipped default: 300)
 #
 #   RSYNC_MAX_RUNTIME_HOURS
 #       Max hours a single transfer attempt may run before it's terminated and paused
 #       for the next scheduled run. Protects the per-profile lock from being held
 #       indefinitely by one huge/stuck transfer, starving other profiles of a turn.
 #       Safe because DEFAULT_RSYNC_OPTS includes --partial — a paused transfer resumes
-#       from where it left off, not from scratch. (default: 23)
+#       from where it left off, not from scratch. (code fallback 23; shipped conf sets 19)
 #
 #   ROOTFS_WARN
 #       Abort threshold for remote rootfs percentage full. (default: 75)