fix: CI test failure — skip WeasyPrint tests when native libs unavailable

- Add requires_weasyprint marker to TestGenerateBusinessPlan and TestWorkerHandler
  (these need libgobject/pango/cairo which CI python:3.12-slim lacks)
- Fix export route tests: use opaque tokens instead of integer IDs
- Replace deprecated datetime.utcnow() with datetime.now(UTC)
- Add missing jsonify/Response imports to admin routes

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

web/src/padelnomics/admin/routes.py

@@ -8,7 +8,17 @@ from datetime import date, datetime, timedelta
 from pathlib import Path
 
 import mistune
-from quart import Blueprint, flash, redirect, render_template, request, session, url_for
+from quart import (
+    Blueprint,
+    Response,
+    flash,
+    jsonify,
+    redirect,
+    render_template,
+    request,
+    session,
+    url_for,
+)
 
 from ..auth.routes import role_required
 from ..core import csrf_protect, execute, fetch_all, fetch_one, slugify
@@ -1410,7 +1420,6 @@ async def scenario_preview(scenario_id: int):
 @role_required("admin")
 async def scenario_pdf(scenario_id: int):
     """Generate and immediately download a business plan PDF for a published scenario."""
-    from quart import request as req
     from ..businessplan import get_plan_sections
     from ..planner.calculator import validate_state
 
@@ -1418,7 +1427,7 @@ async def scenario_pdf(scenario_id: int):
     if not scenario:
         return jsonify({"error": "Scenario not found."}), 404
 
-    lang = req.args.get("lang", "en")
+    lang = request.args.get("lang", "en")
     if lang not in ("en", "de"):
         lang = "en"