fix(review): export verifiable Fable identity and keep advisor configuration Claude-local

[BaseInfinity]

Feedback type

Bug / cross-harness isolation and reviewer provenance.

Problem

Fable is configured on the Claude side (advisorModel: "fable"), but consumer/shared SDLC prose can be read by a Codex driver as though it were an executable Codex reviewer route. That allowed Claude Opus output to be mislabeled as Fable review before the attribution was retracted.

The Claude harness should make genuine Fable execution externally distinguishable from Opus or another fallback. A prompt saying "act as Fable" is not model identity.

Required behavior

• Claude/Fable advisor and fallback configuration remains Claude-owned; it is not copied into or inferred by Codex configuration.
• Genuine Fable review emits a compact machine-readable receipt containing actual provider/model, effort, invocation path, candidate identity, timestamps, and verdict.
• Any fallback records its real model and cannot satisfy a Fable-required gate.
• Exported/shared SDLC guidance declares requirements and points to an adapter contract; it does not claim another host has Fable configured.

Acceptance

• A native Fable High run produces identity metadata that a Codex-side consumer can validate without trusting prompt text.
• Opus/subagent/headless fallbacks retain their actual identity and never carry a Fable label.
• Missing/disabled Fable returns ReviewerUnavailable when Fable is required.
• Setup/update tests prove .claude advisor settings remain Claude-local and no .codex provider config is emitted.
• Add an adversarial regression where output text claims Fable but runner metadata identifies another model.

Paired Codex issue: BaseInfinity/codex-sdlc-wizard#143
Related: #504 (Fable/Opus topology), #616 (review liveness/hangs).