feat: add OpenProse plugin skills

extensions/open-prose/skills/prose/examples/03-code-review.prose

@@ -0,0 +1,17 @@
+# Code Review Pipeline
+# Review code from multiple perspectives sequentially
+
+# First, understand what the code does
+session "Read the files in src/ and provide a brief overview of the codebase structure and purpose."
+
+# Security review
+session "Review the code for security vulnerabilities. Look for injection risks, authentication issues, and data exposure."
+
+# Performance review
+session "Review the code for performance issues. Look for N+1 queries, unnecessary allocations, and blocking operations."
+
+# Maintainability review
+session "Review the code for maintainability. Look for code duplication, unclear naming, and missing documentation."
+
+# Synthesize findings
+session "Create a unified code review report combining all the findings above. Prioritize issues by severity and provide actionable recommendations."