docs: use published SDK peers for local setup

[EgorMajj]

Summary

• Use published SDK peers in contributor and example setup instructions; sibling repositories are optional.
• Explain the existing lockfile and peer-install settings without claiming the packages are unpublished.
• Keep manifests, lockfiles, runtime APIs and workflow behavior unchanged.
  +- Missing-peer error guidance uses the same published-package install command; absent, 1.x and wrong-major fixture cases pass.

Validation

• Fresh standalone install using published npm packages, type checks and package build.
• Packed example build for this framework.
• Additional compatibility checks: React 18, Vue 3.3 and Angular 17/22 in their respective repositories.
• No live identification, credential changes, publication or deployment.