fix(library-decisions): traceSchema accepts the committed trace shape

The strict schema rejected 38 of 39 approved traces in
docs/library-decisions: lastRevalidated was required (most traces omit
it), and the compliance frontmatter fields the _template.md documents
(is-sub-processor, processes-pii, plus the sub-processor block:
data-sent, region, dpa-signed, sccs-required, contact) were
unrecognized keys. Make lastRevalidated optional, add the compliance
fields (booleanish coercion for YAML string scalars), and require
data-sent when is-sub-processor is true. New loop test asserts every
committed trace parses so the schema can never drift away from the
repo's own corpus again.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/library-decisions/schema.mjs

@@ -7,6 +7,12 @@ import fs from "node:fs";
 
 // ---- Zod schema ----
 
+/** YAML scalars arrive as strings — coerce "true"/"false" (or booleans). */
+const booleanish = z.preprocess(
+  (v) => (v === "true" ? true : v === "false" ? false : v),
+  z.boolean(),
+);
+
 const filterResultsSchema = z
   .object({
     license: z.string().min(1),
@@ -30,12 +36,34 @@ export const traceSchema = z
     date: z.string().regex(/^\d{4}-\d{2}-\d{2}$/, "date must be YYYY-MM-DD"),
     deciders: z.array(z.string()),
     adr: z.string().nullable(),
-    lastRevalidated: z.string().nullable(),
+    // Optional: most committed traces have never been revalidated and omit
+    // the key entirely (requiring it rejected 38 of 39 approved traces).
+    lastRevalidated: z.string().nullable().optional(),
     "filter-results": filterResultsSchema,
     "verification-commands": z.array(z.string()),
     "accepted-cves": z.array(z.string()).optional(),
+    // ADR-022 amendment (compliance frontmatter, see _template.md): every
+    // newer trace declares whether the dependency ships data to a third
+    // party; sub-processor traces carry the extra contact/DPA fields.
+    "is-sub-processor": booleanish.optional(),
+    "processes-pii": booleanish.optional(),
+    "data-sent": z.string().nullable().optional(),
+    region: z.string().nullable().optional(),
+    "dpa-signed": z.union([booleanish, z.string()]).nullable().optional(),
+    "sccs-required": z.union([booleanish, z.string()]).nullable().optional(),
+    contact: z.string().nullable().optional(),
   })
-  .strict();
+  .strict()
+  .superRefine((trace, ctx) => {
+    if (trace["is-sub-processor"] === true && trace["data-sent"] == null) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message:
+          "sub-processor traces must declare data-sent (what leaves the machine)",
+        path: ["data-sent"],
+      });
+    }
+  });
 
 // ---- Helpers ----