feat: WP-0006 — packaging & distribution infrastructure

CI matrix (Python 3.11/3.12) with pip cache and coverage job. PyPI publish
workflow (OIDC trusted publishing, triggered on v*.*.* tags). Docker image
for REST service with non-root user + ghcr.io push workflow. markidocx
--version flag. Diagram optional extras (diagram-mermaid/graphviz/plantuml)
and readme/urls in pyproject.toml. CHANGELOG.md (Keep a Changelog format)
with retrospective v0.1.0 entry. docs/release-process.md with executable
checklist. All 272 tests pass; ruff and mypy clean; twine check PASSED.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

pyproject.toml

@@ -6,6 +6,7 @@ build-backend = "setuptools.build_meta"
 name = "markidocx"
 version = "0.1.0"
 description = "Markdown ↔ DOCX round-trip editing system"
+readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "python-docx>=1.1.0",
@@ -27,6 +28,14 @@ dev = [
     "types-PyYAML>=6.0",
     "httpx>=0.27",
 ]
+diagram-mermaid = ["nodeenv>=1.8"]
+diagram-graphviz = ["graphviz>=0.20"]
+diagram-plantuml = []
+
+[project.urls]
+Homepage = "https://github.com/tegwick/marki-docx"
+Source = "https://github.com/tegwick/marki-docx"
+Tracker = "https://github.com/tegwick/marki-docx/issues"
 
 [project.scripts]
 markidocx = "markidocx.cli:app"
@@ -37,6 +46,9 @@ where = ["src"]
 [tool.setuptools.package-data]
 markidocx = ["templates/*.docx"]
 
+[tool.setuptools]
+license-files = ["LICENSE"]
+
 [tool.ruff]
 line-length = 100
 target-version = "py311"