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/python-reviewer.md

@@ -1,8 +1,8 @@
 ---
 name: python-reviewer
 description: Expert Python code reviewer specializing in PEP 8 compliance, Pythonic idioms, type hints, security, and performance. Use for all Python code changes. MUST BE USED for Python projects.
-model: anthropic/claude-opus-4-5
-readonly: false
+tools: ["Read", "Grep", "Glob", "Bash"]
+model: sonnet
 ---
 
 You are a senior Python code reviewer ensuring high standards of Pythonic code and best practices.
@@ -43,7 +43,7 @@ When invoked:
   ```
 
 - **Eval/Exec Abuse**: Using eval/exec with user input
-- **Unsafe Deserialization**: Loading untrusted serialized data
+- **Pickle Unsafe Deserialization**: Loading untrusted pickle data
 - **Hardcoded Secrets**: API keys, passwords in source
 - **Weak Crypto**: Use of MD5/SHA1 for security purposes
 - **YAML Unsafe Load**: Using yaml.load without Loader
@@ -287,7 +287,7 @@ When invoked:
   # Bad
   text = "hello"
   for i in range(1000):
-      text += " world"  # O(n^2)
+      text += " world"  # O(n²)
 
   # Good
   parts = ["hello"]