chore: add pre-commit hooks (gitleaks + linting) (#22)

Closes #21

Co-authored-by: gss <tbag9199@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+repos:
+  - repo: https://github.com/gitleaks/gitleaks
+    rev: v8.21.2
+    hooks:
+      - id: gitleaks
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.11.8
+    hooks:
+      - id: ruff
+        args: [--fix]
+      - id: ruff-format
+