Add BadRequestError and bump vws-python-mock to 2026.2.18.2

Add BadRequestError exception for the BadRequest result code returned by
the VuMark endpoint when invalid JSON is sent. Map it in
generate_vumark_instance and include it in the exception inheritance test.
Bump vws-python-mock to 2026.2.18.2 which adds full VuMark auth endpoint
testing support.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: adamtheturtle

src/vws/exceptions/vws_exceptions.py

@@ -183,3 +183,12 @@ class InvalidInstanceIdError(VWSError):
     """Exception raised when Vuforia returns a response with a result code
     'InvalidInstanceId'.
     """
+
+
+# This is not simulated by client code because the request body
+# is always valid JSON when using this client.
+@beartype
+class BadRequestError(VWSError):  # pragma: no cover
+    """Exception raised when Vuforia returns a response with a result code
+    'BadRequest'.
+    """

src/vws/vws.py

@@ -20,6 +20,7 @@
 from vws.exceptions.vws_exceptions import (
     AuthenticationFailureError,
     BadImageError,
+    BadRequestError,
     DateRangeError,
     FailError,
     ImageTooLargeError,
@@ -806,6 +807,7 @@ def generate_vumark_instance(
 
         exception = {
             "AuthenticationFailure": AuthenticationFailureError,
+            "BadRequest": BadRequestError,
             "DateRangeError": DateRangeError,
             "Fail": FailError,
             "InvalidAcceptHeader": InvalidAcceptHeaderError,

tests/test_vws_exceptions.py

@@ -18,6 +18,7 @@
 from vws.exceptions.vws_exceptions import (
     AuthenticationFailureError,
     BadImageError,
+    BadRequestError,
     DateRangeError,
     FailError,
     ImageTooLargeError,
@@ -341,6 +342,7 @@ def test_vwsexception_inheritance() -> None:
     subclasses = [
         AuthenticationFailureError,
         BadImageError,
+        BadRequestError,
         DateRangeError,
         FailError,
         ImageTooLargeError,