Report V1 Migration

Move machine consumers to Rust Doctor's canonical Report V1 fields.

Report V1 ships with Rust Doctor 0.2.0. Existing JSON consumers can migrate incrementally during the compatibility window.

#Required changes

1. Branch on schema_version and accept additive unknown fields.
2. Read outcome and completeness before interpreting diagnostics or score.
3. Treat partial or failed required work as non-clean.
4. Read score and aggregate counts from summary.
5. Consume canonical diagnostics for identity, normalized locations, evidence, fixes, and visibility surfaces.
6. For baseline scans, inspect baseline_degraded before trusting the delta.

Legacy top-level score, label, dimension, timing, and finding-count fields are temporary aliases. Do not build new integrations against them.

See the Report V1 contract and the 0.2.0 release notes.