Release 2.8.2: move the MPP settle set to pympp 0.11 + x402 2.21

Moves the coupled settle set forward after verifying it end to end (the registry
gate, run in full this time rather than deferred):

- pympp 0.10.1 -> 0.11.0: 0.11 switches credential canonicalization to RFC 8785
  / JCS, which is exactly what mppx 0.9.1 (the JS counterpart) already uses, so
  this ALIGNS the two implementations rather than diverging. pympp has no EIP-712
  zero-amount proof (that domain-v3 mechanism is mppx-only), so the mppx-0.8.0
  break class does not apply. 0.11's Mpp.create now reads .name off each method;
  the one test that stubbed a bare object() is updated to a method-shaped stub.
- x402 2.20.0 -> 2.21.0: the Base mainnet USDC EIP-712 domain is unchanged (all
  USD Coin entries still version "2"); 2.21 only refactored constants.py into
  default_assets.py. No wire change on the rail we settle.

Verification: full suite 1868 passed; ruff, format, ty all clean (ty validates
the 0.11/2.21 API surface our code calls). Standing obligation: a live all-rails
settle against a pympp-0.11 merchant is the final cross-impl confirmation and
runs as a post-deploy smoke.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: vvillait88

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "agentscore-commerce"
-version = "2.8.1"
+version = "2.8.2"
 description = "Agentic commerce SDK for Python: identity middleware (FastAPI, Flask, Django, AIOHTTP, Sanic, ASGI) + payment helpers + 402 builders + discovery + Stripe multichain. The full merchant-side toolkit for AgentScore-powered agentic commerce."
 readme = "README.md"
 license = "MIT"

tests/test_payment_servers.py

@@ -10,6 +10,7 @@
 from __future__ import annotations
 
 import importlib.util
+from types import SimpleNamespace
 from typing import Any
 
 import pytest
@@ -448,11 +449,13 @@ async def test_create_mppx_server_stripe_rail_resolves(monkeypatch: pytest.Monke
 
     ``create_mppx_stripe`` is stubbed because the installed pympp build doesn't ship a
     working ``stripe/charge`` factory; this exercises the stripe branch (resolve + break)
-    in ``create_mppx_server`` without depending on that peer-dep detail.
+    in ``create_mppx_server`` without depending on that peer-dep detail. pympp >=0.11's
+    ``Mpp.create`` reads ``.name`` off each method for its uniqueness check, so the stub
+    returns a method-shaped object carrying one rather than a bare ``object()``.
     """
 
     async def _fake_create_stripe(**_kwargs: Any) -> Any:
-        return object()
+        return SimpleNamespace(name="stripe")
 
     monkeypatch.setattr("agentscore_commerce.stripe_multichain.mppx_stripe.create_mppx_stripe", _fake_create_stripe)
     server = await create_mppx_server(