refactor(audit): centralized AuditBuffer logging and audit.use channel list

[rokde]

Summary

• Replace ad-hoc `RunLogWriter` with a centralized `AuditBuffer` Monolog handler; bind it as a singleton and merge `clonio.json` logging overrides into `config/logging.php`.
• Replace `audit.default` and per-channel `deliver_to` with a single `audit.use` active-channel list driving `AuditDeliveryService`.
• Update Audit Add/Delete/List commands, `InitCommand`, and `ConfigService` for the new shape; refresh docs and the cloning-run PRD.

Test plan

• `composer test` green
• `clonio audit:add` and `audit:list` reflect new `use` semantics
• A cloning run still emits process log + audit artefact via configured channels
• Migrate an existing `clonio.json` with `audit.default` and verify a warning / fallback path is acceptable

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