chore: bump to 1.2.1, pympp 0.6.0→0.7.0, pytempo 0.5.0→0.5.1

Within existing semver bounds (pympp >=0.6,<1; pytempo unchanged
range). Both are optional-dependencies — published distribution only
re-resolves when users install agentscore-commerce[mppx,x402].

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vvillait88

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "agentscore-commerce"
-version = "1.2.0"
+version = "1.2.1"
 description = "Agent 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 agent commerce."
 readme = "README.md"
 license = "MIT"