Update lifecycle terminology to use official state names (#114)

Co-authored-by: Claude Opus 4.5 <[email protected]>

Author: kcmartin

src/content/docs/index.mdx

@@ -41,18 +41,18 @@ Sprites are ideal for:
 - **AI Code Execution** - Running code generated by language models (like Claude Code) in isolated, secure environments
 - **Untrusted Code** - Isolating and executing user-submitted code safely without risking the rest of your system
 - **Development Environments** - Building persistent development environments that maintain state between sessions
-- **Long-lived Services** - Hosting services that hibernate automatically and resume on request
+- **Long-lived Services** - Hosting services that go idle automatically and resume on request
 - **CI/CD Tasks** - Testing code against live git repositories with full environment access
 
 ## Core Concepts
 
 ### Persistence
 
-Every Sprite has a persistent, standard ext4 filesystem. During execution, data is written to fast NVMe storage. When the Sprite hibernates, that data is backed up to durable object storage and automatically restored when it wakes up.
+Every Sprite has a persistent, standard ext4 filesystem. During execution, data is written to fast NVMe storage. When the Sprite goes idle, that data is backed up to durable object storage and automatically restored when it wakes up.
 
-### Automatic Hibernation
+### Automatic Idle Behavior
 
-Sprites automatically hibernate after a period of inactivity (30 seconds by default). While hibernated, there are no compute charges and your full filesystem is preserved. The Sprite wakes instantly on the next request.
+Sprites become `warm` immediately when idle, and may eventually go `cold`. While idle, there are no compute charges and your full filesystem is preserved. The Sprite wakes on the next request—`warm` Sprites resume quickly, `cold` Sprites take a bit longer.
 
 ### HTTP Access
 

src/content/docs/working-with-sprites.mdx

@@ -57,9 +57,9 @@ sprite sessions kill <id>        # kill session
 
 ---
 
-## Sprite Lifecycle: Hibernation and Persistence
+## Sprite Lifecycle: Idle Behavior and Persistence
 
-Sprites automatically hibernate after 30 seconds of inactivity. That means:
+When activity stops, Sprites immediately become `warm`. Over time they may transition to `cold`. `warm` Sprites resume quickly; `cold` Sprites take longer to wake. That means:
 
 ### What Persists (and What Doesn't)
 
@@ -76,7 +76,7 @@ Wake-up is fast:
 - ~100–500ms for normal wakes
 - 1–2s on cold starts
 
-Use TTY sessions to keep things running without hibernating. You can detach with `Ctrl+\` and reattach later to see all the output.
+Use TTY sessions to keep things running without going `cold`. You can detach with `Ctrl+\` and reattach later to see all the output.
 
 ```bash
 sprite exec -tty "rails server"