schemafit v0.3.0

Provider matrix grows 3 → 5: adds Mistral and Cohere rule packs alongside OpenAI, Anthropic, and Gemini. Core package stays zero-dependency (the packs are declarative JSON); the v0.1/v0.2 surfaces (lint/repair/providers/demo, SARIF, --live-verify) are unchanged and green.

• Cohere pack — 10 hard-error rules for the JSON-Schema keywords Cohere structured outputs don't support (composition allOf/oneOf/not, numeric ranges, array-length, string-length, uniqueItems). Every rule is primary-sourced to docs.cohere.com/docs/structured-outputs. Supported keywords (anyOf, $ref/$def, enum, const, pattern) are not flagged.
• Mistral pack (thin) — the strict structured-output conventions lintable at the schema-node level: additionalProperties: false required and every property listed in required. No per-keyword blocklist was invented (Mistral's docs enumerate none); both rules are example-derived and labelled as such.
• The "clean schema passes" CI contract now spans all five providers.

Install: pipx install schemafit · docker pull ghcr.io/orionarchitekton/schemafit:v0.3.0