Add provider inference and acquisition contracts

[jackspirou]

What changed

• Add typed catalog-acquisition authentication methods, including cloud default credential chains and workload identity.
• Add provider inference services, operation endpoints, stream endpoints, author-specific protocols, and offering capabilities.
• Add Mistral, Azure OpenAI, and Ollama provider records.
• Add tenant observation inputs for installation-specific definitions and offerings.
• Regenerate endpoint projections, OpenAPI documents, and package documentation.
• Add v0.3.0 release notes for the direct pre-v1 contract break.

Why

Starmap must own provider-hosted model facts without owning gateway secrets or inference authentication. This contract lets Starport derive provider identity, endpoints, operations, capabilities, prices, and reliability sources from one immutable catalog generation.

Catalog-acquisition credentials stay in Starmap. Gateway and provider inference credentials stay in Starport.

Compatibility

This pull request makes direct pre-v1 Go and generated-projection contract changes. It removes the old endpoint authentication flag, the provider chat-completions field, and the singular offering endpoint. The planned release is v0.3.0.

Validation

• Complete make verify gate passed.
• Normal, pure-Go external-consumer, and short-race suites passed.
• Go vet and the pinned Go linter passed with zero issues.
• Coverage thresholds, documentation generation, build, and catalog validation passed.
• The catalog contains 14 providers, 104 authors, and 611 model definitions with valid cross-references.
• The catalog read benchmark passed at about 9.2 ns/op with zero allocations.
• Changed release prose passed the technical-writing check with zero diagnostics.
• The pre-PR autoreview completed two passes with zero actionable findings.

Release

Merge this protected pull request to main.

Tag the exact merge commit as v0.3.0.

The release workflow must verify and publish the immutable release. Starport can then pin the module.