v0.11.0 - End-to-end execution traceability

End-to-end execution traceability: one trace_id now reconstructs
routing, broadcasts, agents, experts, native pipeline stages,
universal-memory publication, ethical decisions, action proposals,
handlers, results, rejections, and errors. An independent adversarial
review was run against the release candidate before publishing - every
finding reproduced against source and fixed (see AUDIT_v0.11.0.md).

✨ Added

• Immutable ExecutionContext: generated or caller-supplied
  trace_id/run_id, causal parent_id, UTC creation time, opaque
  application/instance/subject/session/turn identifiers, recursively
  frozen size-bounded metadata, and derive() for child operations.
• Run-local propagation via contextvars - bound only while a component
  executes, always reset (including after rejection and exceptions).
• TraceEvent and per-orchestrator TraceRecorder: thread-safe
  structured events, monotonic sequence, SHA-256 hash chain, immediate
  cause_id references, parent-run verification, sanitized export, and
  exporter hooks.
• End-to-end instrumentation across routing, broadcast, agents, experts,
  pipeline stages, universal-memory publication, ethical decisions,
  action proposals, handlers, results, rejections, and errors.
• SETTOrchestrator.process_traced() / TracedResult, get_trace(),
  export_trace(), register_trace_exporter(), verify_traces(),
  last_trace_id.
• Stable generated Action.action_id for causal effect correlation.
• docs/execution_context_v0.11_design.md and MIGRATION_v0.11.md.

🔒 Security

• Traces record operational metadata only - input/action payloads,
  handler return values, exception messages/locals, biometric values,
  risk profiles, prompts, model responses, and private-memory values are
  excluded by default.
• Metadata is bounded (32 top-level keys, depth 8, 16 KiB serialized) and
  rejects sensitive key fragments and non-JSON objects.
• handler.authorized is the committed pre-effect boundary: an exporter
  failure there records handler.blocked, raises
  SETTConfigurationError, and neither handler.started nor the real
  handler ever runs.
• Trace exports are defensive copies; hash and causal verification
  detects mutation, removal, reordering, duplicate IDs, cross-trace/
  forward causes, invalid parent runs, and incomplete instrumented
  operations.

🐛 Fixed

• tests/test_elevenlabs_adapter.py now guards with
  pytest.importorskip("requests") - already fixed as of v0.9.0 (see
  that release), carried forward unchanged.

✅ Compatibility

• SETTAgent.process(), SETTExpert.resolve(), executor handlers,
  SETTOrchestrator.process(), broadcasts, and pipelines remain
  source-compatible. execution_context is additive and keyword-only.
• The complete v0.10.1 suite passes unchanged.
• The private companion-assistant reference application's complete
  baseline suite (842 tests) passes against this source release without
  any application code changes.

Status

• 340 tests passing (290 before), 50 new (tests/test_execution_context_v011.py).
• Independent adversarial review: 8/8 findings reproduced and fixed - see AUDIT_v0.11.0.md.