Test: buddy protocol

[donhardman]

Proposal:

It seems that it's a good idea to cover Buddy protocol with CLT tests. To do so, we can simply send various queries to different endpoints that will be routed to Buddy and check in the log with --debugv mode that we have request data: there and it has the proper structure as follows in our declaration of protocol: https://github.com/manticoresoftware/manticoresearch-buddy?tab=readme-ov-file#communication-protocol-v2

For example, when we send a query to /sql or /sql?mode=raw, we should expect to receive an 'Unknown SQL request' message from the daemon to Buddy, along with a properly parsed body.

Related issue: https://github.com/manticoresoftware/manticoresearch/issues/2603

Checklist:

^{To be completed by the assignee. Check off tasks that have been completed or are not applicable.}

- [ ] Implementation completed - [ ] Tests developed - [ ] Documentation updated - [ ] Documentation reviewed - [ ] [Changelog](https://docs.google.com/spreadsheets/d/1mz_3dRWKs86FjRF7EIZUziUDK_2Hvhd97G0pLpxo05s/edit?pli=1&gid=1102439133#gid=1102439133) updated - [x] OpenAPI YAML updated and issue created to rebuild clients

[sanikolaev]

It's important in this task to test various types of queries that get routed to Buddy:

• sql over mysql

• multi-query sql over mysql (select ...; show meta, use DELIMITER), e.g.:

  mysql> DELIMITER |
  mysql> select * from t; show meta;|
  +------+------------------------+
  | id   | f                      |
  +------+------------------------+
  |    1 | efficiency improvement |
  +------+------------------------+
  1 row in set (0.00 sec)
  --- 1 out of 1 results in 0ms ---
  
  +----------------+-------+
  | Variable_name  | Value |
  +----------------+-------+
  | total          | 1     |
  | total_found    | 1     |
  | total_relation | eq    |
  | time           | 0.000 |
  +----------------+-------+
  4 rows in set (0.00 sec)

• sql over http including /sql, /sql?mode=raw, /cli
• multi-query sql over http (e.g. http://localhost:9308/cli_json?select%20*%20from%20t;show%20meta)
• json over http

[sanikolaev]

It's important in this task to test various types of queries that get routed to Buddy:

Dupe of https://github.com/manticoresoftware/manticoresearch-buddy/issues/369#issuecomment-2430993567 . May have been already done by the moment we get to this task.