Add pre-commit config: standard hooks, detect-secrets, actionlint

detect-secrets baseline reviewed: findings (if any) are false positives.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016TPnPhJbaFEWFLgY6e9WbH

.pre-commit-config.yaml

@@ -0,0 +1,21 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.6.0
+    hooks:
+      - id: check-json
+      - id: check-yaml
+      - id: check-merge-conflict
+      - id: detect-private-key
+      - id: check-added-large-files
+      - id: check-executables-have-shebangs
+      - id: check-shebang-scripts-are-executable
+      - id: end-of-file-fixer
+        exclude: ^gradle/wrapper/gradle-wrapper\.jar$
+      - id: trailing-whitespace
+        exclude: ^gradle/wrapper/gradle-wrapper\.jar$|^gradlew\.bat$
+
+  - repo: https://github.com/Yelp/detect-secrets
+    rev: v1.5.0
+    hooks:
+      - id: detect-secrets
+        args: [ "--baseline", ".secrets.baseline" ]