cli: scaffold phase 1 asset release commands

Add metin-release CLI with argparse dispatcher, result envelope and
error hierarchy, and the full Phase 1 release subcommand set:

  release inspect         - scan source root
  release build-manifest  - wraps make-manifest.py
  release sign            - wraps sign-manifest.py, enforces mode 600
  release diff-remote     - HEAD each blob hash against a base URL
  release upload-blobs    - rsync release dir minus manifest
  release promote         - rsync manifest.json + signature
  release verify-public   - GET + Ed25519 verify, optional blob sampling
  release publish         - composite of the above with per-stage timings

Respects --json / --verbose / --quiet. Exit codes follow the plan
(1 validation, 2 remote, 3 integrity, 4 reserved for ERP).

pyproject.toml

@@ -0,0 +1,42 @@
+[build-system]
+requires = ["setuptools>=61"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "metin-release-cli"
+version = "0.1.0"
+description = "Orchestration CLI for Metin2 client releases"
+readme = "README.md"
+license = { file = "LICENSE" }
+authors = [
+    { name = "Jan Nedbal", email = "jan.nedbal@apertia.cz" },
+]
+requires-python = ">=3.11"
+dependencies = [
+    "cryptography>=41",
+    "requests>=2.31",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8",
+    "pytest-mock>=3",
+]
+
+[project.scripts]
+metin-release = "metin_release.cli:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+addopts = "-q"
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I", "B", "UP"]
+ignore = ["E501"]