refactor(layering): keep the rule catalog free of a cutover-policy helper

The catalog walked the AST with visitAst from record-runtime-policy-ast.ts,
which #1745 renames to cutover-policy-ast.ts -- verified by trial merge: the
import fails to resolve there. A guard-integrity check that breaks when a
neighbouring policy is renamed is the fragility this rule exists to remove,
and a rule catalog has no business depending on a cutover-specific module,
so it collects string literals locally instead.

Author: thymikee

scripts/layering/rule-catalog.ts

@@ -10,11 +10,29 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { parseSync } from 'oxc-parser';
-import { visitAst } from './record-runtime-policy-ast.ts';
 
 /** A rule identifier exactly as the report emits it: a number and one kebab-case name. */
 const RULE_IDENTIFIER = /^R(\d+) ([a-z0-9]+(?:-[a-z0-9]+)*)$/;
 
+/**
+ * Local, so the integrity check does not fail with a neighbouring policy's helper: the shared
+ * walker lives in a cutover-specific module that #1745 renames, and a gate that breaks when a
+ * neighbour is renamed is the fragility this rule exists to remove.
+ */
+function stringLiterals(node: unknown, into: string[]): string[] {
+  if (node === null || typeof node !== 'object') return into;
+  if (Array.isArray(node)) {
+    for (const child of node) stringLiterals(child, into);
+    return into;
+  }
+  const record = node as Record<string, unknown>;
+  if (record['type'] === 'Literal' && typeof record['value'] === 'string') {
+    into.push(record['value']);
+  }
+  for (const child of Object.values(record)) stringLiterals(child, into);
+  return into;
+}
+
 export type RuleDeclaration = Readonly<{ number: number; name: string; file: string }>;
 export type RuleNamespaceCollision = Readonly<{ number: number; names: readonly string[] }>;
 export type LayeringPolicySource = Readonly<{ path: string; source: string }>;
@@ -32,15 +50,14 @@ export function ruleDeclarations(
   const seen = new Set<string>();
   for (const file of sources) {
     const parsed = parseSync(file.path, file.source);
-    visitAst(parsed.program.body, (node) => {
-      if (node['type'] !== 'Literal' || typeof node['value'] !== 'string') return;
-      const match = RULE_IDENTIFIER.exec(node['value']);
-      if (!match) return;
-      const key = `${file.path} ${node['value']}`;
-      if (seen.has(key)) return;
+    for (const value of stringLiterals(parsed.program.body, [])) {
+      const match = RULE_IDENTIFIER.exec(value);
+      if (!match) continue;
+      const key = `${file.path} ${value}`;
+      if (seen.has(key)) continue;
       seen.add(key);
       declarations.push({ number: Number(match[1]), name: String(match[2]), file: file.path });
-    });
+    }
   }
   return declarations;
 }