v0.8.0 - Fail-closed by default

🔒 Security and governance hardening

• SETTExecutor.submit() now raises SETTConfigurationError if the
  Executor is not attached to a SETTOrchestrator, or if the attached
  memory has no EthicalFilter. Previously an unattached Executor would
  run the real handler with no governance at all.
• SETTAgent._publish_to_universal() and propose_action() now raise
  SETTConfigurationError instead of silently returning when the agent
  is not wired. A misconfigured agent no longer looks like it worked.
• UniversalMemory, the ethical audit log, the execution log, and
  history now return defensive deep copies. External code can no longer
  mutate internal state through a returned reference.
• Memory history and both audit logs (ethical decisions and executed
  actions) are now a sequenced SHA-256 hash chain, with a verify_chain()
  helper. Tamper-evident within the running process, not an external
  signature.

🧠 Safety semantics

• Added SafetyAssessment, separating situation_urgency,
  action_harm_risk, omission_risk, and protective_action.
• human_at_risk no longer inflates an action's harm score. The old
  behavior pushed the score to reject_threshold - 0.01 any time a human
  was flagged at risk, which meant a genuinely protective action (like
  calling for help) could get rejected precisely because the situation
  was severe. Domain analyzers now decide harm; urgency stays a separate
  signal.
• New conservative fallback: if human_at_risk is true, the action was
  not classified as protective, and the base verdict is ALLOW, the
  filter promotes it to WARN. The score is untouched, protective actions
  are never affected, and existing REJECT/WARN verdicts are never
  downgraded or relabeled. The audit entry records
  human_at_risk_without_protective_classification under
  decision_reason_codes.

🔧 Fixed

• examples/with_ethics.py Scenario 2 now actually produces WARN,
  matching its own comment. It previously printed "expected: WARN" and
  returned ALLOW.
• get_audit_log() / get_ethical_audit_log() no longer expose
  internal dict references that could be mutated after the fact.

✅ Compatibility

• This release intentionally turns previously silent behavior into
  explicit errors. If your code builds a SETTExecutor or SETTAgent
  outside a fully wired SETTOrchestrator, wire it explicitly or expect
  SETTConfigurationError. No other public signatures changed.

📝 Docs

• MIGRATION_v0.8.md walks through every behavior change with
  before/after examples.
• docs/security_model.md documents the hash chain, defensive copies,
  and the exact human_at_risk promotion rule.
• docs/api_reference.md updated for the new audit log fields
  (situation_urgency, action_harm_risk, omission_risk,
  protective_action, decision_reason_codes).

Status

• 264 tests passing (up from 244 in v0.7.0).
• Wheel built and installed in a clean environment; validated against a
  private reference application (709/709) built on top of this release.
• Python 3.13 declared supported after validation.