docs(reflex): add calibration passport guidance

[0xnavarro]

Public change

Strengthens provider-neutral engine/calibration guidance for Reflex without changing any contract, recipe, fixture or hosted behavior.

Adds:

• a versioned calibration passport tying thresholds to contract/question, engine/checkpoint, runtime/backend, primitive/cardinality, workload slice and calibration corpus/artifact;
• explicit separation between answer-distribution probabilities and a separate correctness/selective-automation signal when an engine exposes both;
• runtime/conversion semantic-fidelity checks before comparing latency/throughput;
• corresponding verification guidance in the general Brida Reflex skill.

Why

A stable Reflex contract can be served by multiple engines and runtimes whose probability scales and numerical behavior differ. Schema/API compatibility is not semantic equivalence, and one engine's threshold or confidence interpretation must not silently transfer to another.

Authority / compatibility

Documentation only.

No public schema, Custom Reflex definition, use-case ID, recipe, fixture expectation, SDK API, hosted execution route, data-class rule or authority boundary changes.

Privacy / provenance review

• provider-neutral wording only;
• no external source attribution;
• no private research URLs/IDs;
• no third-party benchmark claims;
• no engine/vendor-specific product identity.

Validation intent

• public CI / registry validation;
• skill structure/sync checks;
• public-surface/full-history leak scan;
• diff hygiene.

Release intent

• release-impact: none
• release-note: none
• qa-scope: docs

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
🔒 Security Review	✅ Completed 2026-09-22T20:13:58.882532Z	680e4da	PR opened

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[0xnavarro]

Triage (2026-10-01): content is ready. Docs-only (patterns/engine-calibration.md, skills/brida-reflex/references/verification.md). All required checks are green (Node 24, Contributor path + release metadata, CodeQL) and there are no review threads or findings.

Not merged by the closeout agent because of a merge-method conflict. Org rule (brida-ai/brida AGENTS.md) requires merge-commit-only integration. This repo has allow_merge_commit=false plus required_linear_history, and CONTRIBUTING.md says rebase-only. A maintainer needs to pick one of:

1. rebase-merge per this repo's CONTRIBUTING (note: the branch contains two Merge branch 'main' commits that would need dropping); or
2. change the repo settings so they match the org merge-commit rule.