[Feature Request] Add flag to suppress --dangerously-load-development-channels confirmation prompt

Bug Description
Feature request: allow suppressing --dangerously-load-development-channels confirmation
prompt

When using --dangerously-load-development-channels with a custom local MCP server, the
interactive confirmation dialog appears on every launch. For developers building and
iterating on their own channels, this adds friction to every session.

Proposed solutions (any of these would work):

• An env var like CLAUDE_ACCEPT_DEV_CHANNELS=1 to auto-confirm
• A --yes / -y flag to skip interactive prompts
• A settings.json option like "acceptDevChannels": true
• Remembering the user's choice per-channel (e.g. "always trust server:agent-comms")

The "dangerously" prefix already signals intent. An additional interactive gate on every
launch is redundant for local development workflows, especially when combined with
--dangerously-skip-permissions which has no equivalent repeated prompt.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.97
• Feedback ID: 9297b331-d399-4fa6-aea6-9b23f8a61173