feat: introduce family_spec logic for wafer sensor-count partitioning

tests/test_family_spec.py

@@ -0,0 +1,23 @@
+"""Tests for the shared wafer family sensor-count lookup."""
+from pygui.backend.wafer.family_spec import sensor_count_for
+
+
+def test_x_family_returns_80():
+    assert sensor_count_for("X") == 80
+
+
+def test_p_family_returns_244():
+    assert sensor_count_for("P") == 244
+
+
+def test_other_known_families_return_244():
+    for code in ("A", "B", "C", "D", "E", "F"):
+        assert sensor_count_for(code) == 244
+
+
+def test_unknown_family_returns_244():
+    assert sensor_count_for("Z") == 244
+
+
+def test_empty_string_returns_244():
+    assert sensor_count_for("") == 244