[Task]: Investigate feasability of filtering workspace messages by substring in prompt

[alex-mcgovern]

Description

When we added pagination to /v1/workspaces/:workspace_name/messages — we didn't add the ability to filter messages based on a substring contained in the prompt.

This was a feature that was available in the frontend, which was easier to do when we had access to the entire list of messages.

The task here is assess whether this is easy to do or not.

Related:

• feat: add pagination to alerts and messages endpoints #1186
• feat(messages): polish pagination and filtering #1213
• Add pagination to endpoints that read entire tables (alerts/messages) #1020
• [Task]: Refactor complex query logic for /v1/workspaces/:workspace_name/messages #1223

Additional Context

No response