Show intent/reasoning in permission prompt dialogs

Problem

When Claude Code triggers a permission request (e.g., to run a shell command), the dialog shows the command but not why Claude wants to run it. This makes it hard for users to make informed allow/deny decisions.

Current behavior

• Permission dialog shows the command (e.g., ls -la /some/path)
• No explanation of intent or context is provided
• User must guess why Claude wants to run this command

Expected behavior

• The permission dialog should include a brief explanation of why Claude is running the command
• Example: "Checking project structure to detect dev server configurations" → ls -la /some/path

Notes

• The description already exists in Claude's tool call (the description field in the Bash tool) — it just isn't surfaced in the permission UI
• This is especially important for commands that touch the filesystem or run executables, where understanding intent is critical for security decisions