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.test.mjs

@@ -218,3 +218,65 @@ describe("parseTrace", () => {
     assert.throws(() => parseTrace(file), /invalid_type|Required/i);
   });
 });
+
+describe("validateTrace > compliance frontmatter (ADR-022 amendment)", () => {
+  test("accepts is-sub-processor / processes-pii as YAML string booleans", () => {
+    const parsed = validateTrace(
+      validRaw({ "is-sub-processor": "false", "processes-pii": "true" }),
+    );
+    assert.equal(parsed["is-sub-processor"], false);
+    assert.equal(parsed["processes-pii"], true);
+  });
+
+  test("accepts a trace that omits lastRevalidated entirely", () => {
+    const raw = validRaw();
+    delete raw.lastRevalidated;
+    assert.equal(validateTrace(raw).lastRevalidated, undefined);
+  });
+
+  test("accepts a full sub-processor block", () => {
+    const parsed = validateTrace(
+      validRaw({
+        "is-sub-processor": "true",
+        "processes-pii": "true",
+        "data-sent": "error events, stack traces",
+        region: "eu",
+        "dpa-signed": "true",
+        "sccs-required": "false",
+        contact: "https://example.com/dpa",
+      }),
+    );
+    assert.equal(parsed["is-sub-processor"], true);
+    assert.equal(parsed["data-sent"], "error events, stack traces");
+  });
+
+  test("rejects is-sub-processor: true without data-sent", () => {
+    assert.throws(
+      () => validateTrace(validRaw({ "is-sub-processor": "true" })),
+      /data-sent/,
+    );
+  });
+});
+
+describe("parseTrace > every committed trace parses", () => {
+  // The schema exists to validate the traces actually in the repo — a schema
+  // that rejects committed, approved traces is broken (it silently rejected
+  // 38 of 39 before lastRevalidated became optional and the compliance
+  // fields were added).
+  test("all docs/library-decisions traces validate", () => {
+    const docsDir = path.join(
+      path.dirname(new URL(import.meta.url).pathname),
+      "..",
+      "..",
+      "docs",
+      "library-decisions",
+    );
+    const files = fs
+      .globSync(path.join(docsDir, "**", "*.md"))
+      .filter((f) => !f.endsWith("_template.md"));
+    assert.ok(files.length > 0, "expected committed traces to exist");
+    for (const f of files) {
+      assert.doesNotThrow(() => parseTrace(f), `trace failed to parse: ${f}`);
+    }
+  });
+});