Claude Code bug report: SSH passphrase prompt on startup

gistfile0.txt

# Marketplace plugin refresh uses SSH instead of HTTPS, causing unexpected passphrase prompts on startup

When Claude Code starts, it attempts to refresh the official plugins marketplace by cloning/pulling `anthropics/claude-plugins-official`. However, it uses SSH (`git@github.com:...`) rather than HTTPS, which causes an unexpected SSH passphrase prompt when the user's SSH key isn't loaded in the agent.

## Steps to reproduce
1. Have an SSH key configured for GitHub with a passphrase
2. Don't add the key to ssh-agent
3. Run `claude` in a git repository

## Expected behavior
Claude Code should clone public marketplace repositories via HTTPS (`https://github.com/anthropics/claude-plugins-official.git`), which requires no authentication.

## Actual behavior
An SSH passphrase prompt appears before the Claude Code banner:
```
$ claude
Enter passphrase for key '/home/user/.ssh/id_ed25519':
```

## Debug log excerpt
```
[ERROR] Failed to refresh marketplace claude-plugins-official: Failed to clone marketplace repository: SSH authentication failed. Please ensure your SSH keys are configured for GitHub, or use an HTTPS URL instead.

Original error: Cloning into '/home/user/.claude/plugins/marketplaces/claude-plugins-official'...
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.
```

## Environment
- Claude Code v2.1.1
- Ubuntu 24.04.3 LTS
- Linux 6.14.0-37-generic

## Impact
- Confusing/unexpected behavior on startup
- Users may be alarmed seeing SSH authentication prompts from an application they didn't expect to use SSH
- Blocks startup until passphrase is entered or prompt times out

## Suggested fix
Use HTTPS URLs for cloning public marketplace repositories, or fall back to HTTPS when SSH fails.