Moving the copilot-sdk cookbook content in here

cookbook/copilot-sdk/python/persisting-sessions.md

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+# Session Persistence and Resumption
+
+Save and restore conversation sessions across application restarts.
+
+## Example scenario
+
+You want users to be able to continue a conversation even after closing and reopening your application.
+
+> **Runnable example:** [recipe/persisting_sessions.py](recipe/persisting_sessions.py)
+>
+> ```bash
+> cd recipe && pip install -r requirements.txt
+> python persisting_sessions.py
+> ```
+
+### Creating a session with a custom ID
+
+```python
+from copilot import CopilotClient
+
+client = CopilotClient()
+client.start()
+
+# Create session with a memorable ID
+session = client.create_session(
+    session_id="user-123-conversation",
+    model="gpt-5",
+)
+
+session.send(prompt="Let's discuss TypeScript generics")
+
+# Session ID is preserved
+print(session.session_id)  # "user-123-conversation"
+
+# Destroy session but keep data on disk
+session.destroy()
+client.stop()
+```
+
+### Resuming a session
+
+```python
+client = CopilotClient()
+client.start()
+
+# Resume the previous session
+session = client.resume_session("user-123-conversation")
+
+# Previous context is restored
+session.send(prompt="What were we discussing?")
+
+session.destroy()
+client.stop()
+```
+
+### Listing available sessions
+
+```python
+sessions = client.list_sessions()
+for s in sessions:
+    print("Session:", s["sessionId"])
+```
+
+### Deleting a session permanently
+
+```python
+# Remove session and all its data from disk
+client.delete_session("user-123-conversation")
+```
+
+### Getting session history
+
+```python
+messages = session.get_messages()
+for msg in messages:
+    print(f"[{msg['type']}] {msg['data']}")
+```
+
+## Best practices
+
+1. **Use meaningful session IDs**: Include user ID or context in the session ID
+2. **Handle missing sessions**: Check if a session exists before resuming
+3. **Clean up old sessions**: Periodically delete sessions that are no longer needed