Validate base-cli with three independent production consumers

[codeforester]

Parent: #50

Train position: 22 of 22
Phase: P3 — Ecosystem trust

Problem

Broad adoption claims need evidence that the framework works outside Base and that real migration friction feeds back into the product.

Acceptance criteria

• An adopter readiness checklist, migration path, and support channel are published.
• At least three non-Base production consumers are onboarded with permissioned public evidence or maintainable compatibility fixtures.
• Adoption friction is captured as linked issues, with release-blocking findings resolved or explicitly accepted.
• Use cases and outcomes are documented, and downstream compatibility checks are retained where feasible.

Dependencies

• Establish wheel-first release gates across the supported Python and OS matrix #67
• Add property, fuzz, concurrency, signal, and performance test suites #68
• Publish an API stability and deprecation policy #69
• Publish a security policy and runtime threat model #70
• Ship complete production-grade reference applications #71