Add public to_json_snapshot method to Client | Fixes #4143

[sswez02]

Fixes #4143

Problem

Users need to get a JSON snapshot of the Client as a dictionary for sharing experiments programmatically (e.g., storing in databases, sending over network) without writing to a file. Currently they have to use the private method _to_json_snapshot().

Solution

Added a public to_json_snapshot() method to Client in ax/api/client.py that returns the JSON-serializable dictionary.

Usage

from ax.api.client import Client
import json

client = Client()
# ... configure experiment ...

# Get snapshot as dictionary (NEW)
snapshot = client.to_json_snapshot()

# Can now use programmatically
json_string = json.dumps(snapshot)  # Convert to string
# Or store in database, send over network, etc.

Previous Behavior

Users had to use the private method client._to_json_snapshot() which is not part of the public API and could change without notice.

New Behavior

Users can use the public method client.to_json_snapshot() which is part of the supported API.