gates: run poster-facts last, matching the docstring order

scripts/test_repo_gates_docstring.py pins the numbered list in repo_gates.py's
docstring against the GATES table IN ORDER. I listed poster-facts as 17 but
inserted it before decoy-coverage, so the sets matched and the order did not:
'same set, different order'. Caught on DooPlex, where script-tests runs (it
needs fcntl and cannot run on Windows).

Moved the table entry after decoy-coverage rather than renumbering the
docstring: the gate genuinely belongs last, since it only reports.

scripts/repo_gates.py

@@ -173,6 +173,10 @@ GATES = [
     # R-421 — every registered gate across all four repos ships with a decoy test, or is
     # named in the exemption list with its row. Registered LAST, after every runner was green:
     # a failing gate refuses every push, which is what instructions_gate learned the hard way.
+    ("decoy-coverage",  os.path.join(SCRIPTS, "decoy_coverage_gate.py"),
+     [ROOT, os.path.join(os.path.dirname(ROOT), "felhom-controller"),
+      os.path.join(os.path.dirname(ROOT), "felhom-agent"),
+      os.path.join(os.path.dirname(ROOT), "app-catalog-felhom.eu")], True, False),
     # The system poster is a DRAWING made in Claude Design from felhom-system-poster.facts.md;
     # nothing in this repo renders it, so nothing mechanical keeps the two together. This gate warns
     # when the facts file has a newer commit than the poster. It NEVER fails a push, on purpose: a
@@ -180,10 +184,6 @@ GATES = [
     # until a human with another tool was free -- and `--no-verify` is forbidden here, so the only
     # way out would be deleting the gate. Fast: two `git log -1` calls.
     ("poster-facts",    os.path.join(SCRIPTS, "poster_facts_gate.py"),    [ROOT],  True, False),
-    ("decoy-coverage",  os.path.join(SCRIPTS, "decoy_coverage_gate.py"),
-     [ROOT, os.path.join(os.path.dirname(ROOT), "felhom-controller"),
-      os.path.join(os.path.dirname(ROOT), "felhom-agent"),
-      os.path.join(os.path.dirname(ROOT), "app-catalog-felhom.eu")], True, False),
 ]
 
 VERDICT = {0: "OK", 1: "FAILED", 2: "INCONCLUSIVE"}