docs: Add envd 0.5.0 prerequisite to snapshots

docs/sandbox/snapshots.mdx

@@ -8,6 +8,12 @@
 
 The original sandbox continues running after the snapshot is created, and a single snapshot can be used to create many new sandboxes.
 
+## Prerequisites
+
+Snapshots require templates with envd version `v0.5.0` or above. If you are using a custom template created before envd `v0.5.0`, you need to rebuild it.
+
+You can check the template envd version using the `e2b template list` command or by viewing the templates list on the dashboard.
+
 ## Snapshots vs. Pause/Resume
 
 | | Pause/Resume | Snapshots |
@@ -91,7 +97,7 @@
 const snapshot = await sandbox.createSnapshot()
 
 // Create a new sandbox from the snapshot
 const newSandbox = await Sandbox.create(snapshot.snapshotId)
 ```
 ```python Python highlight={5}
 from e2b import Sandbox
@@ -105,17 +111,17 @@
 
 ## List snapshots
 
 You can list all snapshots. The method returns a paginator for iterating through results.
 
 <CodeGroup>
 ```js JavaScript & TypeScript
 import { Sandbox } from 'e2b'
 
 const paginator = Sandbox.listSnapshots()
 
 const snapshots = []
 while (paginator.hasNext) {
   const items = await paginator.nextItems()
   snapshots.push(...items)
 }
 ```
@@ -174,15 +180,15 @@
 |---|---|---|
 | Defined by | Declarative code (Template builder) | Capturing a running sandbox |
 | Reproducibility | Same definition produces the same sandbox every time | Captures whatever state exists at that moment |
 | Best for | Repeatable base environments | Checkpointing, rollback, forking runtime state |
 
 Use templates when every sandbox should start from an identical, known state — pre-installed tools, fixed configurations, consistent environments.
 Use snapshots when you need to capture or fork live runtime state that depends on what happened during execution.
 
 ## Use cases
 
 - **Checkpointing agent work** — an AI agent has loaded data and produced partial results in memory. Snapshot it so you can resume or fork from that point later.
 - **Rollback points** — snapshot before a risky or expensive operation (running untrusted code, applying a migration, refactoring a web app). If it fails, rollback - spawn a fresh sandbox from the snapshot before the operation happened.
 - **Forking workflows** — spawn multiple sandboxes from the same snapshot to explore different approaches in parallel.
 - **Cached sandboxes** — avoid repeating expensive setup by snapshotting a sandbox that has already loaded a large dataset or started a long-running process.
 - **Sharing state** — one user or agent configures an environment interactively, snapshots it, and others start from that exact state.