v0.13.0 - Adapter capability contracts and opt-in resilience

Provider-neutral adapter contracts, honest capability selection, passive
health, structured failures, opt-in resilience, and an expanded voice
roster. Every adapter still ships present and importable, never
framework-selected: an application always names the one it wants.

✨ Added

• Immutable adapter contracts in sett/core_ruler/adapter.py:
  AdapterCapabilities, AdapterRequirements, AdapterHealth,
  AdapterErrorView, AdapterHandle, AdapterSelection. Every
  capability field is tri-state (yes / no / never declared), never a
  plain boolean, and views are detached, JSON-safe copies.
• select_adapter(): pure filtering with a stable, explained rejection
  reason per excluded candidate, passive health/circuit-state checks, and
  caller-owned tie-breaking through SelectionPolicy /
  PrioritySelectionPolicy. SETT ships no provider default or
  recommendation - selection policy belongs to the application.
• SETTAdapterError as the structured common parent of the existing
  SETTLLMAdapterError and SETTServiceAdapterError. Official adapters
  now normalize authentication, quota, timeout, unavailable,
  invalid-response, unsupported-capability and configuration failures,
  always preserving the original provider exception as __cause__.
• CircuitBreaker, CircuitBreakerPolicy, CircuitState and
  execute_with_resilience() in the new sett.core_ruler.resilience.
  Retry and circuit breaking are both off by default; retry additionally
  refuses to run without an explicit idempotency statement.
• Sanitized adapter trace events: call, health, retry, circuit and
  fallback-selection. Prompts, audio, responses, credentials and raw
  provider messages never appear in them.
• Remote voice adapters: Deepgram STT, Azure Speech TTS/STT, AssemblyAI
  STT, Gladia STT, OpenAI-hosted Whisper STT, Cartesia TTS.
• Local voice adapters: pyttsx3 TTS, faster-whisper STT, Kokoro TTS,
  Piper TTS. Model loading is deferred until first use where applicable,
  so importing the module never pays a load cost the application doesn't
  ask for.
• EdgeTTSAdapter, explicitly labeled community/unofficial in its own
  docstring: it calls Microsoft Edge's reader-mode API rather than the
  supported Azure Speech API, and callers should read that distinction
  before using it commercially.
• sett.testing.adapter_contract: a dependency-free contract kit any
  third-party adapter author can run without copying SETT's own test
  suite, covering capability immutability, lifecycle honoring,
  cancellation-before-contact, error normalization, __cause__
  preservation, secret-free views, and honest UNKNOWN health.
• docs/adapters.md and examples/adapter_selection.py.

🐛 Fixed

• The internal execution-context conformance helper _is_uuid() raised
  NameError when called directly instead of importing UUID first.

🔄 Changed

• LLMBase, TTSBase, STTBase and SentimentBase now provide
  concrete capabilities, health and non-billable check_health()
  members. Existing v0.12 third-party subclasses need no changes to gain
  them.
• All eight existing official adapters declare only the behavior their
  current synchronous implementation actually has, and feed the same
  passive health/tracing machinery as the new ones.
• Retry moved from sett.core_ruler.retry to sett.core_ruler.resilience,
  alongside the new circuit breaker so both share one failure
  classification. The old module path remains as a compatibility
  re-export.
• CircuitBreaker is now covered by the documented concurrency
  guarantees and an 8-thread, 2,000-failure stress test. A late failure
  from a call already in flight no longer moves an OPEN circuit's
  timestamp or postpones recovery; a failed HALF_OPEN probe still
  starts a new recovery timeout.
• The living adapter and execution-context design documents moved to
  stable canonical paths (docs/adapter_contract.md,
  docs/execution_context.md) instead of versioned filenames, so future
  revisions update in place instead of creating parallel contracts.
• Prose across the project now favors commas, semicolons, colons,
  parentheses or a sentence break over a dash-shaped pause. Arithmetic
  operators, list markers, changelog dates, ranges and tool directives
  keep their functional symbols unchanged.
• OpenAI, Anthropic and Gemini client construction now preserves
  SETT-owned adapter, cancellation and timeout exceptions unchanged,
  matching their real call paths, while genuine provider construction
  failures still arrive normalized.

✅ Compatibility

• Zero breaking changes in this release.
• Every existing third-party adapter written against v0.12's LLMBase /
  TTSBase / STTBase / SentimentBase keeps instantiating unmodified.
• The 893 tests of v0.12.0 pass unmodified.
• Reference-consumer compatibility: the private companion-assistant
  application's suite (1,175 tests) passes against this source release
  with no application code changes beyond its own declared sett-framework
  version pin. The only local failures came from an audio-hardware gap in
  the verification environment, unrelated to this release.

💖 Sponsors

• Sponsors: eight tiers from a symbolic $1 up to logo
  placement on 4humanityAI.com, with an explicit note on what sponsorship
  does and does not buy.

Known limitations

• No Capability Broker, credential/secret store, or billing/quota
  handling ships in SETT. Provider selection by cost, plan or commercial
  preference is deliberately left to the consuming application.
• Health and circuit-breaker state live in process memory only; neither
  persists across a restart.
• EdgeTTSAdapter depends on an interface Microsoft documents for its
  reader feature, not a supported API contract - stable in practice for
  years, but outside the same guarantee the other adapters carry, and
  flagged as such in its own docstring.
• Declaring a capability as supported describes what an adapter's
  current implementation does, not what a specific provider account,
  plan or region will actually grant at call time.
• The public namespace of the submodules (names without a leading
  underscore that live outside sett.__all__) still has no formal
  policy; that decision remains deferred to the v1.0 freeze.

Status

• 995 tests passing (893 immediately before this release).
• Reference-consumer compatibility: the private companion-assistant
  application's full suite (1,175 tests) passes against this source
  release with zero application code changes beyond its own version pin.
• Zero mandatory dependencies in the core framework. Every provider
  integration, old and new (OpenAI, Anthropic, Gemini, Ollama, Google
  Cloud, ElevenLabs, Deepgram, Azure Speech, AssemblyAI, Gladia, Cartesia,
  pyttsx3, faster-whisper, Kokoro, Piper, edge-tts), is an optional extra.

See CHANGELOG.md for the complete, itemized history of this and every prior version.