v0.1.2

Shipping Lean code

• Added the canonical build-time shipping path for downstream crates with
  lean_toolchain::CargoLeanCapability, lean_rs::LeanCapability,
  lean_rs_worker::LeanWorkerChild, and the ship-crate-with-lean recipe/template.

Documentation builds

• Fixed docs.rs builds by making lean-rs-sys emit documentation-only toolchain metadata when
  DOCS_RS=1, instead of probing for a Lean installation that docs.rs does not provide.
• Added explicit docs.rs metadata for each public crate so docs.rs builds only the default
  Linux target instead of relying on service defaults.
• Added a DOCS_RS=1 workspace documentation gate to CI and the release workflow, plus a
  packaged-tarball docs.rs simulation that hides Lean/elan/lake from PATH before building
  docs from normalized crate contents.
• Included lean-rs-worker benchmark sources in the crate package so declared bench targets
  do not produce packaging warnings.

Loader and deployment hardening

• Added the manifest-backed LeanCapability bundle-loader path, loader preflight diagnostics,
  cross-platform loader regressions, and worker bootstrap checks as the patch-release contract
  for shipped Lean capabilities.
• Made the intended hierarchy explicit in docs and examples:
  CargoLeanCapability manifest → LeanCapability bundle loader → optional
  LeanWorkerCapabilityBuilder / LeanWorkerPool. Lower-level LeanLibrary calls, raw link
  helpers, and low-level worker APIs remain advanced escape hatches.
• Added CI/release gates for packaged-tarball docs.rs simulation, loader regressions,
  workflow validation, package creation, and public-API baseline drift.