refactor(scripts): deslop tooling scripts third pass (#161354)
* refactor(scripts): deslop tooling scripts third pass
Consolidate AST traversal, binding and shadow handling, report grouping,
fixture metadata, and developer harness plumbing. Remove the unused PR
comment verdict parser and one-use forwarding layers while preserving CLI,
guard, baseline, and generated-byte contracts.
* test(scripts): parse mocked fetch requests with Request
* test(scripts): include shared AST helper in protocol fixture
