feat: add prek pre-commit hooks and dependabot (#1720)

* feat: add prek pre-commit hooks and dependabot

Pre-commit hooks (via prek):
- Basic hygiene: trailing-whitespace, end-of-file-fixer, check-yaml, check-added-large-files, check-merge-conflict
- Security: detect-secrets, zizmor (GitHub Actions audit)
- Linting: shellcheck, actionlint, oxlint, swiftlint
- Formatting: oxfmt, swiftformat

Dependabot:
- npm and GitHub Actions ecosystems
- Grouped updates (production/development/actions)
- 7-day cooldown for supply chain protection

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* docs: add prek install instruction to AGENTS.md

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

extensions/open-prose/skills/prose/examples/28-automated-pr-review.prose

@@ -22,11 +22,11 @@ parallel:
   security = session: security_expert
     prompt: "Perform a deep security audit of the changes. Look for OWASP top 10 issues."
     context: overview
-  
+
   perf = session: performance_expert
     prompt: "Analyze the performance implications. Identify potential bottlenecks or regressions."
     context: overview
-  
+
   style = session: reviewer
     prompt: "Review for code style, maintainability, and adherence to best practices."
     context: overview