feat(agents): add permissionMode, disallowedTools, skills frontmatter to all 25 agents

- permissionMode: 1 bypassPermissions, 7 acceptEdits, 7 default, 10 plan
- disallowedTools: 12 agents blocked from Write/Edit/MultiEdit
- model: promote Planner + Code Reviewer to opus
- skills: auto-inject on Executor (7), Code Reviewer (4), Maintainer (2)
- docs: CLAUDE.md + CONFIGURATION.md updated with full agent matrix

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

plugins/pr-review/agents/test-validator.md

@@ -2,6 +2,8 @@
 name: test-validator
 description: Test quality reviewer that validates test coverage, test quality, and testing practices in PR changes.
 model: haiku
+permissionMode: plan
+disallowedTools: Write, Edit, MultiEdit
 ---
 
 # Test Validator Agent