feat(examples): add saas tutorial skeleton

Add a compile-tested v1 tutorial skeleton that proves the production-shaped app boundary without provider-heavy scope: auth/session context, CSRF-checked mutation, local persistence adapter, generated form/slot/keyed row/page/push effects, plain CSS, SSE shape, and one explicit metrics island.

req: examples/001

req: auth/001

req: auth/002

req: auth/004

req: form/001

req: failure/004

req: page_swap/002

req: push/003

README.md

@@ -115,6 +115,9 @@ wire/runtime ABI; and advanced escape hatches that may remain integration-level.
 - `examples/v0`: canonical beginner path covering counter, typed todo CRUD,
   form wizard, auth action, page swaps, SSE notifications, and keyed list
   updates. Start here.
+- `examples/saas`: compile-tested v1 tutorial skeleton covering auth/session,
+  CSRF-safe mutation, local persistence, generated swaps, page/push shape, plain
+  CSS, and one explicit island without provider-heavy platform scope.
 - `examples/kanban`: advanced / north-star milestone boundary sketch. It may
   expose manual registry or render escape hatches while exploring product limits.
 - `examples/techdemo`: advanced integration demo with a leaf island and broader