feat(map): add edge-center delta stats, thickness overlay, and layout fix

- Add edge-center sensor pair tables and delta calculations per wafer family.
- Parse and interpolate wafer thickness CSV data for offscreen visualization.
- Refactor ReadoutPanel layout using Item + anchors to fix right-margin clipping.
- Compact E-C Delta text format to fit standard sidebar width.
- Add pytest suite covering delta calculations, layout pairs, and thickness CSV.

tests/test_frame_stats.py

@@ -2,7 +2,12 @@ import math
 
 import pytest
 
-from pygui.backend.models.frame_stats import Stats, compute_stats
+from pygui.backend.models.frame_stats import (
+    EdgeCenterStats,
+    Stats,
+    compute_edge_center,
+    compute_stats,
+)
 
 
 def test_basic_stat():
@@ -28,3 +33,43 @@ def test_ignores_nan():
     assert s.avg == pytest.approx(150.0)
     assert s.sigma == pytest.approx(1.0)
     assert s.three_sigma == pytest.approx(3.0)
+
+
+# ---- edge-center delta (ADR-0002) ----
+
+PAIRS = ((0, 4), (1, 4), (2, 5), (3, 5))
+
+
+def test_edge_center_min_max_pairs():
+    #        e0     e1     e2     e3     c4     c5
+    values = [150.0, 148.0, 151.0, 149.4, 149.0, 149.5]
+    ec = compute_edge_center(values, PAIRS, excluded=set())
+    # deltas: |150-149|=1.0, |148-149|=1.0, |151-149.5|=1.5, |149.4-149.5|=0.1
+    assert ec == EdgeCenterStats(
+        min_edge_index=3, min_center_index=5, min_edge=149.4, min_center=149.5,
+        min_delta=pytest.approx(0.1),
+        max_edge_index=2, max_center_index=5, max_edge=151.0, max_center=149.5,
+        max_delta=pytest.approx(1.5),
+    )
+
+
+def test_edge_center_skips_excluded_sensors():
+    values = [150.0, 148.0, 151.0, 149.4, 149.0, 149.5]
+    ec = compute_edge_center(values, PAIRS, excluded={2, 3})  # both c5 pairs out
+    assert ec is not None
+    assert ec.max_delta == pytest.approx(1.0)
+    # excluding a center sensor kills all its pairs
+    assert compute_edge_center(values, PAIRS, excluded={4, 5}) is None
+
+
+def test_edge_center_skips_nan_and_out_of_range():
+    values = [150.0, math.nan, 149.0]  # only pair (0, 2) is computable
+    ec = compute_edge_center(values, ((0, 2), (1, 2), (0, 9)), excluded=set())
+    assert ec is not None
+    assert ec.min_delta == ec.max_delta == pytest.approx(1.0)
+    assert (ec.min_edge_index, ec.min_center_index) == (0, 2)
+
+
+def test_edge_center_none_when_no_pairs():
+    assert compute_edge_center([1.0, 2.0], (), excluded=set()) is None
+    assert compute_edge_center([], PAIRS, excluded=set()) is None