Add Layout F1 functional groups and crystal/NC checks.

Write routing-first domain/satellite topology after graph_build, and
flag crystal CL mismatches and NC pins on active nets without inventing
millimetres.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_functional_groups.py

@@ -0,0 +1,58 @@
+"""Layout F1 functional_groups on simple_project — topology only, no mm."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from backend.pinscopex.functional_groups import build_functional_groups
+from backend.pinscopex.models import DesignGraph
+
+SIMPLE = Path(__file__).resolve().parents[1] / "simple_project"
+
+
+def _graph() -> DesignGraph:
+    return DesignGraph.model_validate_json(
+        (SIMPLE / "design_graph.json").read_text(encoding="utf-8"),
+    )
+
+
+def test_simple_project_has_mcu_ldo_bridge_groups():
+    report = build_functional_groups(_graph())
+    assert report.objective == "routing"
+    refs = {g.ref for g in report.groups}
+    assert {"U1", "U2", "U3"} <= refs
+    # No millimetre fields on the report model dump
+    raw = json.loads(report.model_dump_json())
+    blob = json.dumps(raw)
+    assert "max_distance_mm" not in blob or all(
+        r.get("max_distance_mm") is None
+        for g in raw["groups"]
+        for r in g.get("layout_rules") or []
+    )
+
+
+def test_u3_owns_crystal_load_caps():
+    report = build_functional_groups(_graph())
+    u3 = next(g for g in report.groups if g.ref == "U3")
+    sat = {s.ref: s.role_hint for s in u3.satellites}
+    assert "X1" in sat
+    assert sat["X1"] == "crystal"
+    assert sat.get("C9") == "load_cap" or sat.get("C10") == "load_cap"
+    assert "C9" in sat and "C10" in sat
+    assert sat["C9"] == "load_cap"
+    assert sat["C10"] == "load_cap"
+
+
+def test_u1_has_decoupling_or_bulk_on_rails():
+    report = build_functional_groups(_graph())
+    u1 = next(g for g in report.groups if g.ref == "U1")
+    roles = {s.role_hint for s in u1.satellites}
+    assert roles & {"decoupling", "bulk"}
+
+
+def test_domains_cover_all_ics():
+    report = build_functional_groups(_graph())
+    covered = {r for d in report.domains for r in d.ic_refs}
+    assert covered == {"U1", "U2", "U3"}
+    assert all(d.assemble_order for d in report.domains)