Summary

• Adds optional custom_validator + max_validation_retries parameters to AsyncAgent.query. Validator (sync or async) inspects the LLM result; returning a feedback string triggers a re-prompt that includes the feedback so the LLM can self-correct. Bounded by max_validation_retries (default 2 extra calls).
• Useful for callers that need a structural / semantic check beyond what strict_json's schema enforcement provides — e.g. validating that every UUID the LLM emits belongs to a known input set.
• Defaults preserve existing behavior (no validator → single call, same as today).
• Bumps version 3.4.3 → 3.4.4.

Motivation

Consumer use case: SimbianOS filter-observables step where the LLM occasionally garbles a hypothesis_result_id UUID by a single character, crashing downstream DAO lookups. With this hook the caller can pass a UUID-in-input-set validator and TaskGen handles the retry/feedback loop in one place instead of every caller wrapping query in their own retry helper. Tracking comment: https://github.com/simbianai/SimbianOS/pull/4702#discussion_r3288175018

Test plan

• Unit-test AsyncAgent.query with a validator that returns None (no retry, single call)
• Unit-test with a validator that rejects once then accepts (one retry, feedback appended to prompt)
• Unit-test with a validator that always rejects (returns last result after max_validation_retries)
• Smoke-test consumer integration in SimbianOS PR #4702