v0.10.0 - PhrasingExpert fact verification hook

✨ Added

• PhrasingExpert.verify_facts(phrased, facts, context) -> str: an
  optional fourth hook, called after phrased already exists (from the
  LLM if configured and successful, from fallback_text() otherwise),
  letting a subclass validate the ACTUAL text against facts already known
  and swap it out if it contradicts them. Default implementation is a
  pass-through (return phrased), so every existing subclass keeps
  behaving exactly as before with zero changes required. resolve() now
  calls it as part of its template:
  determine_facts -> _phrase -> verify_facts.

  Motivated by a second-hand finding during an external audit: two
  independent subclasses in a downstream project each needed this same
  post-hoc check (a greeting that must never contradict the real time of
  day; a reply that must never assert the wrong name for the user) and,
  with no sanctioned hook for it, each had fully overridden resolve()
  just to insert one verification step - triggering the v0.9.0 override
  warning in the process. Same origin story as PhrasingExpert itself
  (see its class docstring): an unplanned repetition across independent
  call sites is the signal that something belongs in the framework, not
  copy-pasted per project.

• SETTOrchestrator.register_executor(self, executor: SETTExecutor):
  added the missing type hint on executor (residual item from the
  v0.8.0 audit, never part of the 8 accepted fixes at the time). Zero
  behavior change.

✅ Compatibility

Fully backward compatible: verify_facts() is optional with a no-op
default, and does not change PhrasingExpert's existing abstract contract
(determine_facts/build_prompt/fallback_text are still the only
required overrides).

Status

• 280 tests passing (up from 275).