code style: reduce lengthy AI comments

A few merged PRs contain a lot of large "AI slop" type of comments. For example:
https://github.com/ClickHouse/clickhouse-go/pull/1922/changes#diff-70a5c3954aff99cd01e76bc970c6b027903c9fcbffffc205e9d040b9e31fbd50R14

Ideally, comments should never be this large.

## Resolution Criteria
- Removal of existing AI slop comments
- Enhancement of `AGENTS.md`, specifying rules regarding comments
- Comments should be 1-2 lines maximum, and detail blocks of code in a short and efficient way.
- Comments should use ASD-STE100 Simplified Technical English (STE).
- Comments should not refer to stakeholders in the real world. For example, if @must108 reviews a PR and asks for a specific enhancement, the comment should not mention him by name.
- Comments should not refer to specific pull requests or commit IDs.
- **Feel free to edit this description to add more relevant rules!**

## Relevant PRs
https://github.com/ClickHouse/clickhouse-go/pull/1829
https://github.com/ClickHouse/clickhouse-go/pull/1833
https://github.com/ClickHouse/clickhouse-go/pull/1834
https://github.com/ClickHouse/clickhouse-go/pull/1921
https://github.com/ClickHouse/clickhouse-go/pull/1922
https://github.com/ClickHouse/clickhouse-go/pull/1923