Resolve passives from catalog, BOM value, and Murata LQW18AN without an LLM.

Skip the model (and the credit gate) when LCSC/DigiKey already list C/V/Z, when the BOM value is a single R/C/L/FB token, or when the MPN is an LQW18AN inductor. Ferrite beads keep impedance, not invented henries; value-only specs stay out of the shared library.

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

backend/pinscopex/bom_summary.py

@@ -45,7 +45,7 @@ def build_bom_summary(
                 # Drop None values and internal numeric fields
                 raw = {
                     k: v for k, v in raw.items()
-                    if v is not None and k not in ("value_ohms", "value_farads", "value_henries")
+                    if v is not None and k not in ("value_ohms", "value_farads", "value_henries", "impedance_ohm")
                 }
             specs_dict = raw if raw else None