dsh-mint: Integrating the Mint Issue Tracker into DSH Sessions

`dsh-mint` is a DSH plugin designed to address the sandbox overhead of invoking external tools via Bash. By hosting the mint CLI directly within the DSH process, it enables approval-free host tool calls. The plugin provides session context injection, cross-project write confirmation, plan-mode binding, and Git reminders. It requires DSH 0.1.1-rc.2 and Node.js >= 20, and rejects destructive commands.