[Feature Request] Project-level slash command filtering via .claude/settings.local.json

Bug Description
Feature request: Project-level slash command filtering

Allow filtering which slash commands appear in the "/" menu on a per-project basis via .claude/settings.local.json. Currently there's no way to hide plugin or MCP slash commands for specific projects - only globally disabling plugins works.

Use case: Different projects need different commands. Having all plugin commands show up in every project clutters the menu.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.0.54
• Feedback ID: 34e43b62-6fd4-4ea2-affc-521457b8c834

Errors

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