Add Ruff as a formatter

It's complimented by `add-trailing-comma` for better readability and
uses a double run to settle one the final format seamlessly.

.pre-commit-config.yaml

@@ -0,0 +1,26 @@
+---
+
+ci:
+  autoupdate_schedule: quarterly  # low frequency to reduce maintenance noise
+
+repos:
+- repo: https://github.com/astral-sh/ruff-pre-commit.git
+  rev: v0.12.4
+  hooks:
+  - id: ruff-format
+    alias: ruff-format-first-pass
+    name: ruff-format (first pass)
+
+- repo: https://github.com/asottile/add-trailing-comma.git
+  rev: v3.2.0
+  hooks:
+  - id: add-trailing-comma
+
+- repo: https://github.com/astral-sh/ruff-pre-commit.git
+  rev: v0.12.4
+  hooks:
+  - id: ruff-format
+    alias: ruff-format-second-pass
+    name: ruff-format (second pass)
+
+...

.ruff.toml

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+line-length = 79  # Accessibility-friendly
+
+[format]
+quote-style = "single"