Match BOM MPNs to longer LCSC/DigiKey orderable codes.

The lookup required an exact catalog string, so family codes like ESP32-S31-WROOM-3 never picked ESP32-S31-WROOM-3-N16R16V and underscore vs slash MPNs never hit DigiKey.

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

tests/test_digikey_match.py

@@ -0,0 +1,23 @@
+from backend.services.digikey import _find_product
+
+
+def test_find_product_accepts_underscore_vs_slash():
+    products = [{"ManufacturerProductNumber": "25AA1024-I/SM", "DatasheetUrl": "http://a.pdf"}]
+    picked = _find_product("25AA1024-I_SM", products)
+    assert picked is not None
+    assert picked["DatasheetUrl"] == "http://a.pdf"
+
+
+def test_find_product_accepts_family_orderable():
+    products = [
+        {"ManufacturerProductNumber": "24AA025E64-I/SN", "DatasheetUrl": "http://b.pdf"},
+    ]
+    picked = _find_product("24AA025E64", products)
+    assert picked is not None
+    assert picked["DatasheetUrl"] == "http://b.pdf"
+
+
+def test_find_product_rejects_unrelated():
+    products = [{"ManufacturerProductNumber": "GRM21BR61A106KE19L", "DatasheetUrl": "http://c.pdf"}]
+    assert _find_product("10uF", products) is None
+    assert _find_product("CH340", [{"ManufacturerProductNumber": "CH340E"}]) is None