Harden Homeboy worktree adapter defaults

[chubes4]

Summary

• preserve native DMC creation for DMC-owned intent while defaulting the replacement WP-CLI leaf to Homeboy-safe skip behavior
• negotiate handoff freshness strictly with typed legacy fallback and repository-path capability handling
• guard DMC/WP-CLI version skew with exact callable and synopsis validation
• add checksum-pinned production compatibility coverage and CI wiring

Closes #534

Verification

• bash tests/homeboy-worktree-adapter.sh
• bash tests/homeboy-worktree-adapter-integration.sh
• bash tests/ci-coverage.sh
• PHP and Bash syntax checks
• git diff --check origin/main..HEAD

AI assistance

OpenAI gpt-5.6-sol was used through OpenCode to implement, test, recover, rebase, and independently review this change. I directed the work, evaluated review findings, and retained the final implementation after deterministic checks passed.