feat: add model:opus to critical reasoning agents

- projman/planner.md - architecture decisions
- projman/code-reviewer.md - quality review
- pr-review/security-reviewer.md - security analysis
- code-sentinel/security-reviewer.md - security scanning
- data-platform/data-analysis.md - complex data insights

Fixes #303

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

plugins/pr-review/agents/security-reviewer.md

@@ -1,3 +1,9 @@
+---
+name: security-reviewer
+description: Security-focused code reviewer for PR analysis
+model: opus
+---
+
 # Security Reviewer Agent
 
 ## Visual Output Requirements