GitHub Issue Title: "@reference fails with slash-prefixed commands"

Bug Description
@ reference do no work with / commands

Environment Info

• Platform: darwin
• Terminal: tmux
• Version: 1.0.24
• Feedback ID: c5d5fd23-9afe-471e-a42f-f1028626365c

Errors

[{"error":"Error: Command failed: security find-generic-password -a $USER -w -s \"Claude Code\"\nsecurity: SecKeychainSearchCopyNext: The specified item could not be found in the keychain.\n\n    at genericNodeError (node:internal/errors:983:15)\n    at wrappedFn (node:internal/errors:537:14)\n    at checkExecSyncError (node:child_process:882:11)\n    at execSync (node:child_process:954:15)\n    at HZ (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:659:3921)\n    at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:582:8863\n    at Q (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:526:17199)\n    at tJ (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:582:8009)\n    at HS (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:582:7090)\n    at T6 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:582:11202)","timestamp":"2025-06-14T13:17:22.731Z"}]