chore: add Flake8 linting config with baseline ignore rules

Adds .flake8 config and registers the flake8 pre-commit hook scoped to
python/ at rev 7.3.0. Baseline ignore rules (E501, F401, F541, F841,
E722, E402, E741, F811, F821, F824, E231) suppress existing violations
so the hook passes cleanly on the current codebase.

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

.pre-commit-config.yaml

@@ -28,3 +28,10 @@ repos:
     hooks:
       - id: prettier
         exclude: ^(dist/|package-lock\.json|\.venv/|python/)
+
+  - repo: https://github.com/pycqa/flake8
+    rev: "7.3.0"
+    hooks:
+      - id: flake8
+        files: ^python/
+        args: [--config=.flake8]