Fix mixed version topology discovery

[jakubpliszka]

Description

This PR adds per-server MySQL version detection while gh-ost walks the inspector’s upstream replication chain, ensuring that each visited server uses the appropriate replication terminology.

gh-ost previously selected replication terminology using the inspector's MySQL version and reused that version while recursively walking upstream.

In a mixed-version topology, this could issue syntax for one MySQL version against another. For example, an 8.0 inspector caused gh-ost to run SHOW SLAVE STATUS against an 8.4 primary, where that statement is no longer supported.

In case this PR introduced Go code changes:

• contributed code is using same conventions as original code
• script/cibuild returns with no formatting errors, build errors or unit test errors.

[Copilot]

Pull request overview

Adds per-server MySQL version detection during upstream topology discovery, preventing incompatible replication syntax in mixed-version deployments.

Changes:

• Detects each visited server’s version before querying replication status.
• Propagates topology-discovery errors during replication restart.
• Adds mixed-version, MariaDB, and error-path tests.

Show a summary per file

File	Description
go/mysql/utils.go	Uses each topology node’s version for replication terminology.
go/mysql/utils_test.go	Tests mixed-version discovery and failures.
go/logic/inspect.go	Returns replication-status discovery errors.

Review details

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• Files reviewed: 3/3 changed files
• Comments generated: 0
• Review effort level: Balanced