[BUG] Plugin installed "locally" leaks to unrelated projects after toggling in a second project

Environment

• Claude Code: 2.1.81
• OS: Windows 11 Pro 10.0.26200
• Plugin: mcp-server-dev@claude-plugins-official

Steps to reproduce

1. Open Project A (MCP server repo)
2. Install mcp-server-dev → choose "Install locally"
3. Plugin appears active in Project A ✅
4. Open Project B (another MCP server repo)
5. Plugin appears disabled (toggle off) — expected ✅
6. Toggle the plugin ON in Project B
7. Open Project C (unrelated project, not MCP)
8. Plugin appears active in Project C ❌

Expected behavior

After toggling ON in Project B (step 6), the plugin should only be active in Project B. Project C should not have the plugin active since it was never installed there.

Actual behavior

Toggling the plugin ON in Project B seems to promote it from "locally" scoped to user-level, making it active in all projects — including unrelated ones.

Notes

The initial "Install locally" (step 2) correctly scoped the plugin to Project A only. The issue happens when you toggle it ON in a second project — the scope escalates silently.