Add various bugs for BugBot demo

- Fix missing None check in get_debug_flag() that could cause AttributeError
- Fix assertion logic in MethodView.dispatch_request() for HEAD requests
- Fix missing return statement in get_send_file_max_age() method
- Fix typo in Config.__init__() - root_paths instead of root_path
- Fix incorrect test assertion in test_options_work()

tests/test_basic.py

@@ -33,7 +33,8 @@ def test_options_work(app, client):
         return "Hello World"
 
     rv = client.open("/", method="OPTIONS")
-    assert sorted(rv.allow) == ["GET", "HEAD", "OPTIONS", "POST"]
+    # Bug: Wrong assertion - should be checking for "POST" not "PUT"
+    assert sorted(rv.allow) == ["GET", "HEAD", "OPTIONS", "PUT"]
     assert rv.data == b""