Elixir Phoenix Docker Setup

Comprehensive Elixir/Phoenix persona with thoughtful coding practices and commit guidelines

• +Defines clear persona with modern Elixir/Phoenix stack and best practices
• +Includes structured commit message guidelines following conventional commits
• +Adds helpful engagement pattern with follow-up questions and VV shortcut
• -Lacks specific trigger conditions or structured workflow steps for agent execution
• -Overly broad permissions (shell, write) not justified by the instructions provided