docs(examples): add the CMS proof-of-concept dogfooding artifact

A WordPress-inspired CMS whose entire backend is PiCloud Rhai scripts
deployed with pic apply, plus a SvelteKit frontend. Built to dogfood the
project tool, CLI, and SDK; exercises docs/kv/files/users, docs+queue+cron
+pubsub triggers, the transactional-outbox notification chain, a docs
before-interceptor, set_if CAS, SSE, per-app CORS, env overlays, and a
durable Workflow (validate -> enrich || seo -> publish -> finalize) started
with workflow::start and polled with workflow::run_status, visualized live
with Svelte Flow.

FINDINGS.md / SECURITY.md capture every gap, surprise, and security issue
found (each tagged [PiCloud] vs [CMS]); the platform fixes for the
actionable ones ship in the preceding commit.

Also folds in the read-only `pic` allowlist entries added to
.claude/settings.json during the session (fewer-permission-prompts).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/cms-poc/scripts/posts/post_update.rhai

@@ -0,0 +1,44 @@
+// PUT /cms/admin/posts/:id — update a post (author+ ; own-only unless admin).
+import "auth" as auth;
+import "util" as util;
+let g = auth::guard(ctx, ["admin", "author"]);
+if !g.ok { return g.response; }
+let user = g.user;
+
+let id = ctx.request.params.id;
+let posts = docs::collection("posts");
+let doc = posts.get(id);
+if doc == () { return #{ statusCode: 404, body: #{ error: "not found" } }; }
+let cur = doc.data;
+
+// IDOR guard: an author may edit only their OWN post; an admin edits any.
+let is_admin = users::has_role(user.id, "admin");
+if !is_admin && cur.author_id != user.id {
+    return #{ statusCode: 403, body: #{ error: "not your post" } };
+}
+
+let b = ctx.request.body;
+if b.title != () { cur.title = b.title; }
+if b.body_md != () { cur.body_md = b.body_md; }
+if b.excerpt != () { cur.excerpt = b.excerpt; }
+if b.tags != () { cur.tags = b.tags; }
+
+let idx = kv::collection("slugs");
+if b.slug != () {
+    let newslug = util::slugify(b.slug);
+    if newslug != cur.slug {
+        idx.delete("post:" + cur.slug);
+        if idx.has("post:" + newslug) { newslug = newslug + "-" + random::string(4).to_lower(); }
+        idx.set("post:" + newslug, id);
+        cur.slug = newslug;
+    }
+}
+
+if b.status != () && b.status != cur.status {
+    cur.status = b.status;
+    if b.status == "published" && cur.publish_at == () { cur.publish_at = time::now(); }
+    if b.status == "scheduled" && b.publish_at != () { cur.publish_at = b.publish_at; }
+}
+
+posts.update(id, cur);
+#{ statusCode: 200, body: #{ id: id, slug: cur.slug, status: cur.status } }