chore(middleware): 0.1.0

Picks up emit_custom_event (#1052), the only change since 0.0.3, and moves
the Python package onto the same minor-release policy as the JS libraries.

The Railway images pin threadplane-middleware==0.0.1 in
deployments/ag-ui-dev/requirements.txt and its deps/ exports, so the helper
is not importable there yet. Those pins must be bumped only AFTER 0.1.0 is
live on PyPI, or the image build breaks — a separate change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: blove

packages/threadplane-middleware/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "threadplane-middleware"
-version = "0.0.3"
+version = "0.1.0"
 description = "LangGraph middleware for binding client-declared tool stubs and routing client tool calls to END so the browser executes them."
 readme = "README.md"
 license = { text = "MIT" }