feat(plugins): create branch-naming-validator hook plugin

[JacobPEvans]

Create Claude Code hook plugin for branch naming validation.

Repository: jacobPEvans/claude-code-plugins

Implements

• PreToolUse hook on Bash (git checkout -b, git branch)
• Validates branch names
• AI-friendly error messages
• Example correct formats

Tasks

• Create plugin structure
• Implement validation logic
• Add comprehensive tests
• Document hook usage

Related

• Depends on: Branch naming enforcement issues
• Reference: https://github.com/jacobPEvans/claude-code-plugins

Epic

Implements #30