Initial import: shopdb-flask multi-site asset platform

Flask + Vue rewrite of the classic-ASP shopdb, built as a plugin
framework so sister GE Aerospace sites can adopt it. Product version
0.7.0-pre-0.8.0, plugin contract 0.11.0, 966 backend tests.

Key entry points:
- docs/INSTALL-WINDOWS-IIS.md - tested Windows + IIS install runbook
  (own-site and subpath deployment methods)
- docs/PILOT-DEPLOY.md - production pilot: stand up + import + verify
- docs/IMPORT-API.md - schema-agnostic legacy data import contract
- scripts/site_imports/wjf/ - West Jefferson reference import loader
- docs/adr/ - twelve accepted architecture decision records

shopdb/utils/pagination.py

@@ -0,0 +1,43 @@
+"""Pagination utilities."""
+
+from flask import request, current_app
+from typing import Tuple
+
+
+def get_pagination_params(request_obj=None) -> Tuple[int, int]:
+    """
+    Extract pagination parameters from request.
+
+    Returns:
+        Tuple of (page, per_page)
+    """
+    if request_obj is None:
+        request_obj = request
+
+    default_size = current_app.config.get('DEFAULT_PAGE_SIZE', 20)
+    max_size = current_app.config.get('MAX_PAGE_SIZE', 100)
+
+    try:
+        page = max(1, int(request_obj.args.get('page', 1)))
+    except (TypeError, ValueError):
+        page = 1
+
+    try:
+        per_page = int(request_obj.args.get('perpage', request_obj.args.get('per_page', default_size)))
+        per_page = max(1, min(per_page, max_size))
+    except (TypeError, ValueError):
+        per_page = default_size
+
+    return page, per_page
+
+
+def paginate_query(query, page: int, per_page: int):
+    """
+    Apply pagination to a SQLAlchemy query.
+
+    Returns:
+        Tuple of (items, total)
+    """
+    total = query.count()
+    items = query.offset((page - 1) * per_page).limit(per_page).all()
+    return items, total