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/5e21d1ed89bdac1cdad37d9250ae3538526a20c129fca1e41c1b98377389e79f.json

@@ -0,0 +1 @@
+{"issues": [{"issue_id": "DEDUP-01", "source_stage": "code", "category": "building_code", "severity": "critical", "confidence": "high", "location": "General Codes & Standards Notes", "disciplines": ["General", "Electrical", "Plumbing", "Architectural"], "sheets": ["G21.01", "E01.01", "P03.01", "A23.01", "G11.04"], "description": "The drawing set references multiple conflicting versions of the International Building Code (IBC). Findings from conflict, code, and constructability reviews confirm that sheets reference the 2018 IBC (G21.01) and 2021 IBC (E01.01, P03.01, A23.01, G11.04), while the adopted code for the jurisdiction (Harris County) is believed to be the 2015 IBC. All design elements must be based on a single, correct, and legally adopted code edition.", "evidence": [{"discipline": "General", "sheet": "G21.01", "source_text": "2018 INTERNATIONAL BUILDING CODE (IBC) CH. 2-10 WITH HARRIS COUNTY AMENDMENTS", "asserted_value": "2018 IBC"}, {"discipline": "Electrical", "sheet": "E01.01", "source_text": "CONTRACTOR SHALL CONFORM TO ALL LOCAL, STATE, AND APPLICABLE CODES, 2023 NEC, 2021 IBC, 2021 IECC, NFPA, ETC.", "asserted_value": "2021 IBC"}, {"discipline": "Plumbing", "sheet": "P03.01", "source_text": "PER 2021 IBC, CHAPTER 19, SECTION 1907: POLYETHYLENE VAPOR RETARDER MINIMUM 6-MIL SHALL BE REQUIRED.", "asserted_value": "2021 IBC"}, {"discipline": "Architectural", "sheet": "A23.01", "source_text": "INTERIOR FINISHES TO COMPLY WITH IBC CLASS C OR HIGHER SECTION 803.9 AND TABLE 803.9 OF 2021 IBC.", "asserted_value": "2021 IBC"}, {"discipline": "General", "sheet": "G11.04", "source_text": "AREA LIMITATION: UNLIMITED (TABLES 504.3, 504.4, 506.2 IBC 2021)", "asserted_value": "IBC 2021"}], "recommended_resolution": "Verify the currently adopted and enforced code edition with the Harris County Engineering Department. Revise the design, drawings, and all code analysis to comply with the single, correct, legally adopted code version.", "code_reference": null}, {"issue_id": "QAQC-001-M", "source_stage": "qaqc", "category": "missing_sheet", "severity": "critical", "confidence": "high", "location": "Drawing Set", "disciplines": ["Architectural", "Mechanical"], "sheets": ["G11.01"], "description": "Essential architectural and mechanical plan sheets are missing from the drawing set. The sheet index indicates pages 14 (likely Architectural Dimension/Construction Plan), 15 (likely Architectural Reflected Ceiling Plan), and 22 (Mechanical HVAC Plan) failed extraction. The lack of these sheets makes it impossible to verify critical information like ceiling heights, dimensions, and HVAC layouts. The set is incomplete and cannot be bid, permitted, or built.", "evidence": [{"discipline": "System", "sheet": "sheet_index", "source_text": "Page 14 (extraction failed), Architectural, floor_plan", "asserted_value": "Missing Architectural Construction/Dimension Plan"}, {"discipline": "System", "sheet": "sheet_index", "source_text": "Page 15 (extraction failed), Architectural, reflected_ceiling_plan", "asserted_value": "Missing Architectural Reflected Ceiling Plan"}, {"discipline": "System", "sheet": "sheet_index", "source_text": "Page 22 (extraction failed), Mechanical, mep_plan", "asserted_value": "Missing Mechanical Floor Plan"}], "recommended_resolution": "Incorporate the missing plan sheets (A-Dimension Plan, A-Reflected Ceiling Plan, M-HVAC Plan) into the drawing set and update the sheet index. Provide the Reflected Ceiling Plan, clearly indicating the height of all ceiling types.", "code_reference": null}, {"issue_id": "QAQC-002-M", "source_stage": "qaqc", "category": "missing_sheet", "severity": "critical", "confidence": "high", "location": "Drawing Set", "disciplines": ["Structural", "Architectural", "Mechanical", "Electrical"], "sheets": ["G01.01", "A25.01", "M03.01", "E05.02", "G11.01"], "description": "The drawing set contains no Structural discipline sheets (S-series). This is a critical omission as new rooftop units (RTUs) are specified, which impose new loads on the existing roof structure. Notes on M, E, and A sheets explicitly reference coordination with a structural engineer, who is not listed on the cover sheet. Without structural drawings, the project is unbuildable and unsafe.", "evidence": [{"discipline": "System", "sheet": "sheet_index", "source_text": "Missing Expected Sheet: Structural Discipline", "asserted_value": "No S-sheets are present"}, {"discipline": "Mechanical", "sheet": "M03.01", "source_text": "ANGLE IRON FRAME ALL AROUND ROOF OPENING RE: STRUCTURAL.", "asserted_value": "Reference to Structural"}, {"discipline": "Electrical", "sheet": "E05.02", "source_text": "VERIFY SUPPORT SIZING AND DESIGNED WITH PROJECT STRUCTURAL ENGINEER PRIOR TO ASSEMBLY.", "asserted_value": "Requires verification with Structural Engineer"}], "recommended_resolution": "Engage a structural engineer to review the existing structure, design support for new equipment, and produce the necessary structural drawings (S-serieLine truncated