feat: general-purpose sub-agent

[sovadim]

Applicable issues

• fixes #

Description of changes

Checklist

• Title of the pull request follows Conventional Commits specification
• Design documented is updated/created and approved by the team (if applicable)
• Documentation is updated/created (if applicable)
• Changes are tested on review environment
• App schema changes are backward compatible, or breaking changes are documented with a migration guide
• Integration tests pass

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