Add bulk UV sampler, TKHelix and MakeSphere (8.0.1.2)

- n3xd_ocp.sample.face_grid: a face's UV grid of points and outward
  normals in one GIL-free call, sampling exactly where np.linspace does
  so a caller's fitted surface does not move.
- n3xd_ocp.helix: OCCT 8.0's TKHelix, which upstream does not bind at
  all. Takes Python lists rather than NCollection_Array1. Two things the
  header does not say, both found by probing: SetParameters wants N+1
  diameters for N segments (one per boundary, so a taper interpolates),
  and the builder is right-hand only -- a negative pitch is error status
  12, not a mirrored helix.
- Bind BRepPrimAPI_MakeSphere and give inventory.py an EXTRA_SYMBOLS
  addendum for symbols no app source imports. assay's gen_flow_fixtures
  has been unrunnable since the 10C cutover for want of it; the gap was
  wider than --check, since sigdiff is inventory-driven too.

Gates: 105 tests, 139/139 symbols, sigdiff clean, ASAN clean, wheel
self-contained with no libGL/libX11 DT_NEEDED.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HbTQ2HYWQwdtGmGJwypt6Z

tools/inventory.py

@@ -32,6 +32,15 @@ HERE = pathlib.Path(__file__).resolve().parent
 DEFAULT_INVENTORY = HERE.parent / "inventory.json"
 DEFAULT_APP = HERE.parent.parent / "app" / "backend"
 
+#: Symbols no app source imports, so the scan below cannot see them, but which
+#: another consumer of this wheel needs.  Hand-maintained: add the symbol and
+#: name who wants it, so a later reader can tell a real dependency from a
+#: leftover.  Merged into the scan, so --emit keeps them.
+EXTRA_SYMBOLS: dict[str, dict[str, list[str]]] = {
+    # assay/scripts/gen_flow_fixtures.py builds spheres for its CFD fixtures.
+    "BRepPrimAPI": {"BRepPrimAPI_MakeSphere": []},
+}
+
 
 def scan(app_root: pathlib.Path) -> dict:
     """Collect {module: {symbol: [attributes reached on it]}} from the app."""
@@ -70,6 +79,10 @@ def scan(app_root: pathlib.Path) -> dict:
                 mod, name = local[node.value.id]
                 modules[mod][name].add(node.attr)
 
+    for mod, symbols in EXTRA_SYMBOLS.items():
+        for name, attrs in symbols.items():
+            modules[mod][name].update(attrs)
+
     return {
         "app_root": str(app_root),
         "files_importing_ocp": files,