captain templates: fragments instead of [Unreleased]; no slot call for stamped trains

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

captain/templates/READY.md

@@ -20,6 +20,10 @@ SHIP_RECEIPT: pr=<n> head=<sha12> version=- base=<BASE> tree=<tree> session_kind
 READY_RECEIPT: <path the tool wrote> (<local and notes-ref detail>)
 ```
 
+Under `changelog_fragments` (docs/ship-policy.md#changelog-fragments) the PR's entry is a
+fragment, `changelog.d/<slug>.md`, never an `[Unreleased]` section or a version, and the
+controller merges with `train land` or `land`, so no slot call follows this block.
+
 The lane's own lines, after the block:
 
 ```text

captain/templates/slot-call.md

@@ -1,7 +1,9 @@
 # Slot call
 
 Sent by the controller to one lane at a time, in train order, after the train verdict is
-GREEN and the previous slot has merged and verified.
+GREEN and the previous slot has merged and verified. Plain trains only: a train built under
+`changelog_fragments` has no slot call; the controller runs `train land --train <nonce> --pr <n>`
+(docs/ship-policy.md#train-land).
 
 ```text
 #<n> slot <X>, base <BASE sha40>, order <remaining order, e.g. 41,42,43>