Slash command picker: filter by namespace prefix

Feature request

When a project has many slash commands organized under a namespace (e.g., rs:compose, rs:render, rs:qa-visual, …), typing /rs: in the command picker should filter the list to only show commands in that namespace.

Current behavior

Typing /rs: returns "Unknown skill: rs:". The fuzzy matcher surfaces rs:* commands but mixed in with everything else.

Expected behavior

Typing a namespace prefix like /rs: (with trailing colon) should filter the autocomplete list to only commands matching that namespace, rather than trying to invoke a skill literally named rs:.

Context

Plugins can register many commands under a single namespace (via .claude/plugins/<name>/commands/). As the number of commands grows, namespace filtering becomes essential for discoverability. This is analogous to VS Code's command palette filtering by category prefix.

---

🤖 Generated with Claude Code