Release 2.8.1: consume python-sdk 2.6.7 (settle set held) (#129)

## Summary

Releases `agentscore-commerce` 2.8.1, consuming the just-published
`agentscore-py` 2.6.7 (the lock now resolves it; the `>=2.6.4` floor
already allowed it) and publishing the already-merged minor-patch group
(#127). The uv.lock own-version is synced to 2.8.1.

The coupled MPP settle set is deliberately HELD at its
coordinated-verified versions: **pympp 0.10.1, x402 2.20.0** stay put.
`uv lock --upgrade` would move them (to pympp 0.11.0 / x402 2.21.0,
dragging eth-rlp/rlp/hexbytes majors), but the registry requires a
signing/domain byte-compare plus a live all-rails settle before the
settle set moves. That belongs in a dedicated coupled bump, not a
routine refresh.

## Type of change

- [ ] Bug fix (no breaking change)
- [ ] New feature (no breaking change)
- [ ] Breaking change (existing callers must update)
- [x] Docs, tests, or internal maintenance only

## Public API

None. No exported symbols or wire formats changed. The `agentscore-py`
floor is unchanged (`>=2.6.4`); only the resolved lock version moved.

## Test plan

Ran `uv run ruff check`, `uv run ruff format --check`, `uv run ty
check`, and `uv run pytest`: all clean, 1868 passed (4 skipped), 95.37%
coverage (above the 95% bar).

## Checklist

- [x] Tests cover the new behavior, and the suite passes locally
- [x] Lint, format, and type checks pass
- [x] Docs and README examples updated if the public surface changed
- [x] No secrets, credentials, or personal data in the diff or the tests

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 = "2.8.0"
+version = "2.8.1"
 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"