Add Agent / Customer channel selection to Discovery search

Add the ability to search in Discovery separately by conversation channel:

• Agent

• Customer

Currently, search in Discovery does not allow users to specify which side of the conversation should contain the searched value.

Using tags for this purpose is inconvenient, especially for one-time searches.

Required Changes

Extend the existing Discovery search field with a channel selector.

Users should be able to choose:

• Agent

• Customer

The selected channel should define where the search is performed.

The behavior can follow the existing filtering approach used for tags.

Expected Behavior

Examples:

• Search term: refund

• Channel: Customer

Result: only conversations where the searched value is found in the customer channel.

• Search term: refund

• Channel: Agent

Result: only conversations where the searched value is found in the agent channel.

If no specific channel is selected, the current search behavior should remain unchanged.

Acceptance Criteria

1. Discovery search supports separate Agent and Customer channel selection.

2. Search results only match the selected conversation channel.

3. Existing search behavior remains available when no channel is selected.