agent-os v0.11.0

The proportional-testing release: protect changed behavior without turning every small fix into a large test-generation exercise.

• New automatic proportional-testing discipline requires a realistic, previously unprotected regression before adding another test.
• Prefers existing and table-driven tests, observable contracts, and the cheapest sufficient test level.
• Integrates focused bug-fix coverage into deliver-work while preserving required repository, CI, and release checks.

This is a GitHub-only release. npm publication is intentionally excluded; @sockulags/agent-os remains at 0.9.1 on npm.