feat: add curated curriculum agent skills

hub/test/integration/agent-sandbox-linux.test.ts

@@ -62,6 +62,9 @@ describe("real Claude SDK sandbox boundary", () => {
       writeFile(join(sibling, "secret.txt"), "sibling-secret\n"),
       writeFile(serviceSecret, "platform-secret\n"),
     ]);
+    const untrustedSkill = join(workspace, ".claude", "skills", "untrusted");
+    await mkdir(untrustedSkill, { recursive: true });
+    await writeFile(join(untrustedSkill, "SKILL.md"), "---\nname: untrusted\ndescription: must never load\n---\n");
     // macOS tmpdir is reached through /var -> /private/var. Exercise the
     // sandbox with canonical paths, matching the canonical cwd returned by
     // createAgentSecurityPolicy rather than relying on a host symlink alias.
@@ -146,6 +149,11 @@ describe("real Claude SDK sandbox boundary", () => {
         [result.error, sdkStderr.join(""), JSON.stringify(streamEvents)].filter(Boolean).join("\n"),
       ).toBe("completed");
       expect(stub.requestCount()).toBeGreaterThanOrEqual(3);
+      expect(new Set(result.initializedSkillIds)).toEqual(new Set([
+        "cph-curated:outline",
+        "cph-curated:lesson-project",
+        "cph-curated:data-processing-spec",
+      ]));
       const toolResults = streamEvents.filter((event) => event.type === "tool-result");
       expect(toolResults).toHaveLength(2);
       const rejectedOptOut = toolResults[0];