Added settings for black and mypy. Added optional 'rich'

Configured the linter, formatter and type checker (black and mypy). Add optional dependency for rich; which makes it easier to view data.

pyproject.toml

@@ -19,6 +19,11 @@ dependencies = [
 [project.scripts]
 bpe-jigsaw = "bpe_jigsaw.cli:main"
 
+[project.optional-dependencies]
+cli = [
+    "rich>=14.2.0",
+]
+
 [build-system]
 requires = ["uv_build>=0.9.4,<0.10.0"]
 build-backend = "uv_build"
@@ -29,9 +34,31 @@ testpaths=["tests"]
 norecursedirs=[".git", ".venv"]
 addopts = ["import-mode=importlib"]
 
+[tool.mypy]
+mypy_path = [ "src", "tests" ]
+
+[tool.ruff]
+line-length = 120
+indent-width = 4
+
+target-version = "py312"
+
+[tool.ruff.lint.pydocstyle]
+convention = "google"
+
+[tool.ruff.format]
+quote-style = "double"
+indent-style = "space"
+skip-magic-trailing-comma = false
+line-ending = "auto"
+docstring-code-format = false
+docstring-code-line-length = "dynamic"
+
 [dependency-groups]
 dev = [
+    "pip>=25.3",
     "pytest>=8.4.2",
     "pytest-cov>=7.0.0",
+    "ruff>=0.14.4",
 ]