[Feature] Desktop: expose /hooks, /mcp, /plugins slash-commands (or equivalents) for power users

Problem

In ZCode desktop, several slash-commands documented for Claude Code are not available. Most notably:

• /hooks — read-only browser for configured hooks (would let users verify their config without restarting).
• /mcp — MCP server status, connection check, reconnect.
• /plugins — browse/install/manage plugins.

Currently the only way to manage these is through Settings → MCP / Plugins GUI, which works for enable/disable but doesn't show runtime status (connection state, hook execution log, hook config validation errors).

Why this matters

I just spent ~3 hours debugging why my UserPromptSubmit hook wasn't firing. Root cause turned out to be an invalid args field in config.json that silently disabled the entire hooks section (see issue #32, where I left a detailed comment). A /hooks command showing:

• Which hooks are registered.
• Their matchers.
• The last execution result (success/failed/not-triggered).

would have caught this in 30 seconds instead of 3 hours.

Similarly, /mcp showing live connection state would help diagnose the MCP subprocess leak (#104) — users could see "5 desktop-commander processes running" without leaving the chat.

What exists today (verified on ZCode 3.3.6, Windows 11 Pro)

• Settings → MCP Servers (GUI): add/edit/delete/enable/disable.
  No runtime status, no "test connection" button.
• Settings → Plugins (GUI): enable/disable, marketplace browse.
  No hook viewer.
• ~/.zcode/cli/log/zcode-YYYY-MM-DD.jsonl: contains config.file.invalid, hook.run.failed, mcp.configured_servers.connect.completed events with detailed diagnostics. But this is a JSONL file users have to grep manually — not friendly.

Proposal

Add slash-commands (or in-chat UI) that surface the runtime state already being logged:

• /hooks — list registered hooks with last-execution status.
• /mcp — list MCP servers with connection state and process count.
• /plugins — list installed plugins with enabled state and last error.

These are read-only views over data ZCode already collects. Would significantly improve power-user debuggability without changing the underlying engine.

Related

• Issue #32 — my comment about args field regression.
• Issue #104 — MCP subprocess leak (users want to see process count).
• Issue #108 — slash-command menu accessibility (related UX).
• Skills zcode-guide:diagnosing-hooks, diagnosing-mcp, diagnosing-plugins — already document the intended commands.

Environment

• ZCode 3.3.6, Windows 11 Pro.
• 6 MCP servers, 3 custom hooks, 4 plugins.

Thanks!

Start by reviewing the existing Settings → MCP Servers and Settings → Plugins views, the documented slash-command skills, and the JSONL events in ~/.zcode/cli/log/zcode-YYYY-MM-DD.jsonl. The issue does not name source files or tests; the work would need a decided scope for the /hooks, /mcp, and /plugins views and a way to verify their displayed runtime state.