Release v5.4.1: MCP search server toggle functionality

New Features:
- REST API endpoints for MCP server status and toggle control
- UI toggle in viewer sidebar for enabling/disabling MCP search server
- File-based persistence mechanism (.mcp.json ↔ .mcp.json.disabled)
- Independent state management for MCP toggle

Technical changes:
- Added GET /api/mcp/status endpoint (returns mcpEnabled boolean)
- Added POST /api/mcp/toggle endpoint (toggles MCP server state)
- Updated Settings interface with mcpEnabled property
- Enhanced Sidebar component with MCP toggle UI and state management
- Updated worker service with MCP control logic
- Bumped version to 5.4.1 in all metadata files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

CLAUDE.md

@@ -6,7 +6,7 @@ Claude-mem is a Claude Code plugin providing persistent memory across sessions.
 
 **Your Role**: You are working on the plugin itself. When users interact with Claude Code with this plugin installed, your observations get captured and become their persistent memory.
 
-**Current Version**: 5.4.0
+**Current Version**: 5.4.1
 
 ## Critical Architecture Knowledge