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/tests/conftest.py

@@ -6,16 +6,17 @@ import hmac
 import sqlite3
 import tempfile
 import time
-from datetime import datetime
+from datetime import UTC, datetime
 from pathlib import Path
 from unittest.mock import AsyncMock, patch
 
 import aiosqlite
 import pytest
-from padelnomics import core
 from padelnomics.app import create_app
 from padelnomics.migrations.migrate import migrate
 
+from padelnomics import core
+
 _SCHEMA_CACHE = None
 
 
@@ -87,7 +88,7 @@ async def client(app):
 @pytest.fixture
 async def test_user(db):
     """Create a test user, return dict with id/email/name."""
-    now = datetime.utcnow().isoformat()
+    now = datetime.now(UTC).isoformat()
     async with db.execute(
         "INSERT INTO users (email, name, created_at) VALUES (?, ?, ?)",
         ("test@example.com", "Test User", now),
@@ -119,7 +120,7 @@ def create_subscription(db):
         provider_subscription_id: str = "sub_test456",
         current_period_end: str = "2025-03-01T00:00:00Z",
     ) -> int:
-        now = datetime.utcnow().isoformat()
+        now = datetime.now(UTC).isoformat()
         # Create billing_customers record if provider_customer_id given
         if provider_customer_id:
             await db.execute(
@@ -147,9 +148,10 @@ def create_subscription(db):
 async def scenario(db, test_user):
     """User scenario with valid planner state for PDF generation."""
     import json
+
     from padelnomics.planner.calculator import validate_state
     state = validate_state({"dblCourts": 4, "sglCourts": 2})
-    now = datetime.utcnow().isoformat()
+    now = datetime.now(UTC).isoformat()
     async with db.execute(
         """INSERT INTO scenarios (user_id, name, state_json, created_at)
            VALUES (?, 'Test Scenario', ?, ?)""",