AAP-85334: Replace Black + Flake8 with Ruff

Migrate Python linting and formatting toolchain from Black (formatter)
and Flake8 (linter) to Ruff, which provides both in a single tool.

- pyproject.toml: remove [tool.black], add [tool.ruff] config sections
- tox.ini: replace black+flake8 deps/commands with ruff in linters env
- awxkit/tox.ini: replace flake8 with ruff in lint env
- Makefile: replace `black` target with `format` + `lint`, keep `black`
  as legacy alias, update `check` and `api-lint`
- pre-commit.sh: use `ruff format --check`, honor AWX_IGNORE_RUFF
- requirements_dev.txt: swap black/flake8 for ruff
- Dockerfile.j2: install ruff instead of black
- CONTRIBUTING.md: update tool references
- Fix noqa comments to use # separator instead of ; (ruff requirement)
- Add noqa: F841 for false positive in awxkit/cli/__init__.py

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

pyproject.toml

@@ -6,8 +6,17 @@ build-backend = "setuptools.build_meta"
 # causes the "version" key in setup.cfg to be ignored.
 # [tool.setuptools_scm]
 
-[tool.black]
+[tool.ruff]
 line-length = 160
-fast = true
-skip-string-normalization = true
-extend-exclude = "awx_collection"
+extend-exclude = ["awx_collection"]
+
+[tool.ruff.format]
+quote-style = "preserve"
+
+[tool.ruff.lint]
+select = [
+    "E722",
+    "F401", "F402", "F405", "F523", "F541",
+    "F811", "F821", "F822", "F841",
+    "W291", "W605",
+]