Initial commit: Conflict Checker

Cross-discipline design-contradiction checker for construction drawing
sets. Standalone tool broken out from Iron_Bid; a pipeline stage may
later fold back into Iron_Bid.

Pipeline: PDF->images -> per-sheet assertion extraction -> deterministic
clustering by location -> per-cluster reasoning -> report.
Includes CLI (cli/run_check.py) and web UI (backend/main.py).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/.llm_cache/8a55617f156c9954bc8ebaac53941506813a88f2900fc6e0163c761646d7221d.json

@@ -0,0 +1 @@
+{"normalized_assertions": [{"assertion_id": "A51.01#16", "original_value": "33\"-36\"", "normalized_value": null, "normalized_unit": null, "normalized_attribute": null, "normalization_notes": "Range in inches, no clear conversion to other units.", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "A51.01#17", "original_value": "17\"-19\"", "normalized_value": null, "normalized_unit": null, "normalized_attribute": null, "normalization_notes": "Range in inches, no clear conversion to other units.", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "A51.01#18", "original_value": "7\"-9\"", "normalized_value": null, "normalized_unit": null, "normalized_attribute": null, "normalization_notes": "Range in inches, no clear conversion to other units.", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "A51.01#19", "original_value": "3'-6\" MIN.", "normalized_value": "3'-6\"", "normalized_unit": "feet and inches", "normalized_attribute": "length", "normalization_notes": "Removed 'MIN.' qualifier, preserved unit as feet and inches.", "source_text_preserved": true, "normalization_confidence": "high"}, {"assertion_id": "A51.01#20", "original_value": "3'-4\"", "normalized_value": "3'-4\"", "normalized_unit": "feet and inches", "normalized_attribute": "length", "normalization_notes": "Preserved unit as feet and inches.", "source_text_preserved": true, "normalization_confidence": "high"}, {"assertion_id": "M01.01#0", "original_value": "ROOFTOP A/C UNIT", "normalized_value": null, "normalized_unit": null, "normalized_attribute": null, "normalization_notes": "No unit or numerical value to normalize.", "source_text_preserved": true, "normalization_confidence": "high"}, {"assertion_id": "M01.01#1", "original_value": "CARRIER", "normalized_value": null, "normalized_unit": null, "normalized_attribute": null, "normalization_notes": "No unit or numerical value to normalize.", "source_text_preserved": true, "normalization_confidence": "high"}, {"assertion_id": "M01.01#2", "original_value": "50FE-M07", "normalized_value": null, "normalized_unit": null, "normalized_attribute": null, "normalization_notes": "No unit or numerical value to normalize.", "source_text_preserved": true, "normalization_confidence": "high"}, {"assertion_id": "M01.01#3", "original_value": "711", "normalized_value": "711", "normalized_unit": "pounds (lbs)", "normalized_attribute": "weight", "normalization_notes": "Assumed unit based on context (weight).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#4", "original_value": "2100", "normalized_value": "2100", "normalized_unit": "cubic feet per minute (CFM)", "normalized_attribute": "supply_airflow", "normalization_notes": "Assumed unit based on context (airflow).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#5", "original_value": "3.0", "normalized_value": "3.0", "normalized_unit": "horsepower (hp)", "normalized_attribute": "fan_horsepower", "normalization_notes": "Assumed unit based on context (horsepower).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#6", "original_value": "6.0", "normalized_value": "6.0", "normalized_unit": "tons", "normalized_attribute": "cooling_capacity_nominal", "normalization_notes": "Assumed unit based on context (cooling capacity).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#7", "original_value": "10.6", "normalized_value": "10.6", "normalized_unit": "kilowatts (kW)", "normalized_attribute": "heating_capacity", "normalization_notes": "Assumed unit based on context (heating capacity).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#8", "original_value": "460", "normalized_value": "460", "normalized_unit": "volts (V)", "normalized_attribute": "voltage", "normalization_notes": "Assumed unit based on context (voltage).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#9", "original_value": "3", "normalized_value": "3", "normalized_unit": "phase", "normalized_attribute": "phase", "normalization_notes": "Assumed unit based on context (electrical phase).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#10", "original_value": "24", "normalized_value": "24", "normalized_unit": "amps (A)", "normalized_attribute": "mca", "normalization_notes": "Assumed unit based on context (minimum circuit ampere).", "source_text_preserved": true, "normalization_confidence": "medium"}, {"assertion_id": "M01.01#11", "original_value": "25", "normalized_value": "25", "normalized_unit": "amps (A)", "normalized_attribute": "mocp", "normalization_notes": "Assumed unit based on context (maximum overcurrent protection).", "source_text_preserved": true, "normalization_conLine truncated