feat(core): compose selected project-validation reports

[rcs2153]

Summary

• add an additive Core adapter for selected project-validation routing plus WorkReport composition
• preserve exact same-call local-check references and defer reports while approval is pending
• reassess existing terminal runs against the durable source-bound evaluation context without rerunning workflow skills
• document the bounded implementation and next review phase

Scope

Core-only, local, explicit, and opt-in. No CLI behavior, provider execution, SideEffect execution, schemas, examples, hosted behavior, or release posture changes.

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• focused selected report-adapter tests: 4 passed
• cargo test --workspace
• npm run check:docs
• git diff --check

Governed phase

• workflow: dg/implement
• run: run-1786446058514276000-2
• approval: approval/run-1786446058514276000-2/implementation-approved
• presentation: presentation/f924d31a1d6b015c
• phase close: completed, proof enforced, 39 events, 0 retries, 0 escalations