feat: filter messages by ID

[alex-mcgovern]

While integrating the pagination changes in #1020 I realised that we need the ability to find specific messages for display in the UI. Previously we just filtered the entire set, but after adding pagination to this endpoint, that is no longer possible.

This PR adds a filter_by_ids param to GET /v1/workspaces/:name/messages, which accepts a list of IDs to filter by. I thought about GET /v1/workspaces/:name/messages/:id — but I think given the semi-complex logic of parsing disparate prompts & outputs and matching them to messages, this might be simpler, as well as allowing other opportunities to find specific messages and highlight them in the dashboard at a later point.

Examples

Without filtering:

curl -s "http://localhost:8989/api/v1/workspaces/default/messages?page=1&page_size=2" | jq '[.data[].chat_id]'
[
  "aa85b6a5-423a-4cd0-a27f-51088b5fe30c",
  "5ac437ff-6b1c-4aa4-b276-d43bce33f28e"
]

Filtering by a single ID:

curl -s "http://localhost:8989/api/v1/workspaces/default/messages?page=1&page_size=2&filter_by_ids=aa85b6a5-423a-4cd0-a27f-51088b5fe30c" | jq '[.data[].chat_id]'
[
  "aa85b6a5-423a-4cd0-a27f-51088b5fe30c"
]

Filtering by multiple IDs:

curl -s "http://localhost:8989/api/v1/workspaces/default/messages?page=1&page_size=2&filter_by_ids=aa85b6a5-423a-4cd0-a27f-51088b5fe30c&filter_by_ids=5ac437ff-6b1c-4aa4-b276-d43bce33f28e" | jq '[.data[].chat_id]'
[
  "aa85b6a5-423a-4cd0-a27f-51088b5fe30c",
  "5ac437ff-6b1c-4aa4-b276-d43bce33f28e"
]

Filtering by non-existent ID:

curl -s "http://localhost:8989/api/v1/workspaces/default/messages?page=1&page_size=2&filter_by_ids=2
F2FDF94-429D-45E4-9D61-DFA4DB3E6D2F" | jq
{
  "data": [],
  "limit": 2,
  "offset": 0,
  "total": 63
}