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/pipeline/validator.py

@@ -0,0 +1,36 @@
+"""
+validator.py - Stage 9: issue deduplication and validation (LLM).
+
+Consolidates findings from Stages 5-8 (conflicts, full-set QAQC, code, and
+constructability) into one clean, deduplicated canonical-issue list, dropping
+unsupported or vague items. On failure it returns the input unchanged so no
+findings are lost.
+"""
+
+from typing import Dict, List
+
+from backend import config
+from backend.pipeline._serialize import dumps
+from backend.pipeline._stage import call_stage, collect_list, validate_issue
+from backend.prompts import (
+    DEDUP_VALIDATE_SYSTEM_PROMPT,
+    DEDUP_VALIDATE_USER_INSTRUCTION,
+)
+
+
+def dedup_validate(all_issues: List[Dict]) -> List[Dict]:
+    if not all_issues:
+        return []
+    parsed = call_stage(
+        DEDUP_VALIDATE_SYSTEM_PROMPT,
+        DEDUP_VALIDATE_USER_INSTRUCTION,
+        subs={"issues": dumps(all_issues)},
+        max_tokens=config.VALIDATE_MAX_TOKENS,
+    )
+    validated = collect_list(parsed, "issues", validate_issue)
+    if not validated:
+        # Model failed or returned nothing usable -- keep the raw findings.
+        print(f"[Validate] dedup produced no list; keeping {len(all_issues)} raw issue(s)")
+        return all_issues
+    print(f"[Validate] {len(all_issues)} raw -> {len(validated)} consolidated issue(s)")
+    return validated