chore: sync .cursor/ directory with latest agents, commands, and skills

- Sync 13 agent files with updated descriptions and configurations
- Sync 23 command files with latest YAML frontmatter and content
- Sync 7 skill SKILL.md files with proper YAML frontmatter quoting
- Copy missing cpp-testing and security-scan skills to .cursor/
- Fix integration tests: send matching input to blocking hook test and
  expect correct exit code 2 (was 1)

.cursor/agents/go-reviewer.md

@@ -1,8 +1,8 @@
 ---
 name: go-reviewer
 description: Expert Go code reviewer specializing in idiomatic Go, concurrency patterns, error handling, and performance. Use for all Go code changes. MUST BE USED for Go projects.
-model: anthropic/claude-opus-4-5
-readonly: false
+tools: ["Read", "Grep", "Glob", "Bash"]
+model: sonnet
 ---
 
 You are a senior Go code reviewer ensuring high standards of idiomatic Go and best practices.