Support MySQL 26.x (new calendar-based versioning)

## Summary
MySQL has switched to calendar versioning (CalVer) starting with version 26.7 (July 2026), replacing the previous 8.x/9.x sequential scheme. Version numbers now follow `YY.M.P` (e.g. 26.7.0, 26.10.0).

Databus currently reports:
- unsupported MySQL major version: 26 (supported: 5.x, 8.x, 9.x)

## Question
- Is support for MySQL 26.x (and future CalVer releases) planned?
- If not yet planned, would a PR be welcome? Any guidance on where the version check/parsing logic lives would help.

## Reference
https://dev.mysql.com/doc/refman/26.7/en/mysql-releases.html

Start by locating Databus's MySQL version check and parsing logic, since the issue does not name specific files or tests. Trace how supported major versions are determined, then verify that MySQL 26.x examples such as 26.7.0 and 26.10.0 are accepted without breaking existing 5.x, 8.x, and 9.x handling.

Written by the indexing model from the issue text.