- New `src/system/analysis.{hpp,cpp}` — stateless post-processing pass
`analyze_system(System*) → AnalysisReport`. Per-module detection of
signal groups and anomalies; pure read, re-runnable.
- Groups: diff pairs (`*_P` / `*_N`, case-insensitive), buses
(`NAME[N]` or strict `NAME_N` — the `_` before digits is required
so names like `GETH_01_VDD12` are not misread as a bus).
- Anomalies: `DiffPairOrphan` (asymmetric: only `_P` without `_N` is
reported — `_N` alone is overloaded with active-low semantics and
floods the output with false positives), `BusGap` (missing index
inside a detected `[lo..hi]`).
- Noise filters: signals starting with `$` (Mentor internals) are
skipped wholesale.
- New `analyze` shell command — prints groups sorted by module +
label, then anomalies. Sized for the upcoming dashboard.
- `tests/test_analysis.cpp` — 8 cases covering both detectors, false-
positive guards (no-underscore digits, `$`-prefixed internals), and
per-module scoping.
- `tests/test_nc_origin.cpp` — completes the prior NC-tagging commit
with round-trip + drop_singleton_signals coverage.
- DESIGN.md updated: layout entry for `analysis.{hpp,cpp}` and new
section explaining the pass; NC-origin paragraph aligned with the
actual tag semantics and the verify three-pass summary.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
