feat: Add Document Crawler & Auto-Onboarding service (Phase 1.4)

New standalone Python/FastAPI service for automatic compliance document
scanning, LLM-based classification, IPFS archival, and gap analysis.
Includes extractors (PDF, DOCX, XLSX, PPTX), keyword fallback classifier,
compliance matrix, and full REST API on port 8098.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

document-crawler/extractors/xlsx_extractor.py

@@ -0,0 +1,22 @@
+"""XLSX text extraction using openpyxl."""
+
+from openpyxl import load_workbook
+
+
+def extract_xlsx(file_path: str) -> str:
+    """Extract text from an XLSX file."""
+    wb = load_workbook(file_path, read_only=True, data_only=True)
+    sheets = []
+
+    for sheet_name in wb.sheetnames:
+        ws = wb[sheet_name]
+        rows = []
+        for row in ws.iter_rows(values_only=True):
+            cells = [str(c) for c in row if c is not None]
+            if cells:
+                rows.append(" | ".join(cells))
+        if rows:
+            sheets.append(f"[{sheet_name}]\n" + "\n".join(rows))
+
+    wb.close()
+    return "\n\n".join(sheets)