Code snippet sharing — /snippet command

[BillChirico]

Part of #40

A /snippet slash command for the community to save and share reusable code snippets. Like a community-owned GitHub Gist inside Discord.

Subtasks

• Create snippets table: id, name (unique per guild), language, code, author_id, guild_id, usage_count, created_at, updated_at
• /snippet save — modal or text input for name, language (autocomplete), and code block
• /snippet get — return code in Discord code block with syntax highlighting, increment usage_count
• /snippet search — fuzzy search via ILIKE or pg_trgm across name and code content
• /snippet list — paginated embed showing recent and most-used snippets
• /snippet delete — author or admin only
• Autocomplete on snippet names for get/delete commands
• Graceful fallback without DATABASE_URL — ephemeral reply saying feature requires DB

Acceptance Criteria

• Users can save, retrieve, search, and delete snippets
• Syntax highlighting works correctly
• Usage tracking shows popular snippets