backend-gap-report

@amd-agi

Compare a Primus backend against an upstream repository or reference, verify git state, dependencies, directory changes, and integration coupling, then generate comparison reports, dashboard metadata, and a deployable dashboard index. Also owns the shared Primus engineering dashboard under `tools/backend_gap_report/`, which surfaces both backend-gap reports and weekly engineering reports as first-class sections. Use when comparing TorchTitan, Megatron, or other Primus backends with upstream branches, tags, or releases, or when integrating weekly engineering reports into the shared dashboard.