chore(qualitygate): align the bootstrap baseline with the merged registry

The approved bootstrap snapshot records the registry size at the moment the
file first reaches the target branch, and it is the only check that runs in
that situation. This change now carries both the registry and the first round
of cleanup, so the file lands on main holding 18 edges rather than the 39 it
was pinned to.

Update the count and hash to match, and state in a comment why the baseline
stays hardcoded: a value CI could supply would let anyone raise the approved
size without the change appearing in a diff.

scripts/check-layering-ratchet.sh

@@ -87,8 +87,12 @@ layering_ratchet_main() (
   fi
 
   local base_revision="${1:-${QUALITY_GATE_CHANGED_FROM:-}}"
-  local approved_initial_count="${2:-39}"
-  local approved_initial_hash="${3:-5636d50d10b9de1e08dc9f06cd66671b3f438650fa5b7f28b95aa7d5a69a1c21}"
+  # The approved size of the registry at the moment it first reaches the target
+  # branch. Only consulted while the target branch has no registry file, so it
+  # is read exactly once: on the change that introduces the file. Hardcoded on
+  # purpose — a configurable baseline could be raised in CI without review.
+  local approved_initial_count="${2:-18}"
+  local approved_initial_hash="${3:-3e7c5e9cb420248b817a3fdbe936069dbb295398751eee4f66b36cfa571d111b}"
   if [[ -z "$base_revision" ]]; then
     echo "Layering ratchet requires a base revision." >&2
     return 1