v1.x: generate authoritative CLI, release, and Rust API documentation

[projectious]

Extracted from the final review of #135. Consolidates former issue #169.

Scope

Define and document the supported developer-facing v1.x surface while removing
manually maintained drift points. Generate CLI help, release facts, and public
Rust API documentation from authoritative implementation sources.

Acceptance criteria

• User-facing command reference is generated from the shipped CLI.
• Version, artifact names, checksums, and support status have one authoritative
  source.
• A public Rust library target exposes the supported v1.x API.
• Public items have rustdoc and runnable examples.
• Semver expectations and explicitly unstable/internal modules are documented.
• Library tests cover the documented primary integration path.
• CI detects stale generated help, release facts, and API documentation.
• The docs build consumes generated facts without hand-copied release values.
• Published package metadata and generated API docs pass release validation.
• Contributor documentation explains regeneration and review.

Parent: #135

[projectious]

Implemented in #175 and corrected to the repository's strict local-only policy in #176. CLI help and release facts are generated from authoritative sources; the public Rust library has rustdoc and runnable tests; package metadata validates; and scripts/test-installer-local.sh now fails on stale generated runtime/baseline/CLI/release docs while building rustdoc and checking package contents. No GitHub Actions or workflow files are used.