v0.2.0 - ConnectionManager Migration

What's New

Connection System Refactor

• MQTT Migration: MQTT nodes now use ConnectionManager with automatic subscription lifecycle management
• WebSocket Migration: WebSocket nodes now use ConnectionManager with listener lifecycle management
• HTTP Template System: Create reusable HTTP request templates with {{placeholder}} parameter substitution

New Features

• Connection Persistence: Connections are now saved per flow in IndexedDB
• HTTP Templates: Define API endpoint templates with parameters, headers, and body templates
• Test Connection: Test connection button in the connection editor
• Connection Status: Visual indicators showing connection state on nodes

New Components

• TemplateSelect - Dropdown for selecting HTTP templates
• HttpTemplateEditor - Modal for creating/editing HTTP templates
• ConnectionSelect - Protocol-aware connection picker with status indicator
• ConnectionEditor - Unified connection configuration form
• ConnectionList - Grouped list of connections with quick actions

Technical Improvements

• State machine integration for connection lifecycle
• Proper resource cleanup and disposal functions
• Backwards compatible HTTP direct URL mode
• 171 passing tests