Allow configuring slash command suggestion limit

Feature Request

When typing / in Claude Code CLI, only ~6 slash command suggestions are displayed. As the number of installed skills/plugins grows, it becomes harder to discover and access them through the autocomplete menu.

Problem

• The slash command suggestion limit appears to be hardcoded
• Users with many custom skills and plugins cannot see all available commands at a glance
• No setting exists in settings.json or elsewhere to configure this limit

Proposed Solution

Add a configurable setting (e.g., slashCommandSuggestionLimit or maxSlashCommandSuggestions) in settings.json to control the number of visible slash command suggestions.

Example:

{
  "slashCommandSuggestionLimit": 15
}

Workarounds

Currently the only workaround is to type more characters after / to filter the list, but this requires knowing the command name in advance.