Fix duplicated "unexpected shutdowns" paragraph in Rules of Durable Objects

The paragraph under "Design for unexpected shutdowns" rendered twice: an inline hardcoded copy plus the working-without-shutdown-hooks partial, which begins with the same sentence.

Remove the inline paragraph so the partial is the single source of truth, and preserve the "at any time" wording by adding it to the partial.

Author: krupa-dot

src/content/docs/durable-objects/best-practices/rules-of-durable-objects.mdx

@@ -1441,8 +1441,6 @@ export class ChatRoom extends DurableObject<Env> {
 
 ### Design for unexpected shutdowns
 
-Durable Objects may shut down at any time due to deployments, inactivity, or runtime decisions. Rather than relying on shutdown hooks (which are not provided), design your application to write state incrementally.
-
 <Render file="working-without-shutdown-hooks" product="durable-objects" />
 
 ## Anti-patterns to avoid

src/content/partials/durable-objects/working-without-shutdown-hooks.mdx

@@ -2,7 +2,7 @@
 {}
 ---
 
-Durable Objects may shut down due to deployments, inactivity, or runtime decisions. Rather than relying on shutdown hooks (which are not provided), design your application to write state incrementally.
+Durable Objects may shut down at any time due to deployments, inactivity, or runtime decisions. Rather than relying on shutdown hooks (which are not provided), design your application to write state incrementally.
 
 Shutdown hooks or lifecycle callbacks that run before shutdown are not provided because Cloudflare cannot guarantee these hooks would execute in all cases, and external software may rely too heavily on these (unreliable) hooks.