Summary

• add cargo xtask adoption-regression with human and JSON receipt output
• run bounded copied-user-path checks: user-path-smoke, runtime scanner-safe matrix, webhook tests, TLS/OIDC bundle proofs, and no-blob
• write metadata receipts under target/adoption-regression/ while keeping generated fixture payloads under target/

Files added/changed

• xtask/src/main.rs: registers the adoption-regression command and --format json option
• xtask/src/adoption_regression.rs: implements the receipt runner, runtime scanner-safe matrix, markdown/json receipts, and focused tests

Validation

• cargo test -p xtask adoption_regression
• cargo clippy -p xtask --all-targets -- -D warnings
• cargo xtask adoption-regression
• cargo xtask adoption-regression --format json with stdout parsed as JSON
• cargo +nightly xtask pr-lite
• cargo xtask pr
• git diff --check

Non-goals

• no new fixture families or contract packs
• no release machinery changes
• no new public claims or badges
• no arbitrary command execution from TOML

What this enables next

• gives the adoption-correctness lane a single bounded receipt for copied user paths, scanner-safe runtime metadata, and stable contract-pack proof coverage