feat(extension): update MCPServerPackage for connection mode tracking

[CalvinAllen]

Parent Epic

Part of #18 - STDIO Transport Support

Description

Modify MCPServerPackage to track connection mode and coordinate between HTTP and STDIO modes.

Implementation

Modify: src/CodingWithCalvin.MCPServer/MCPServerPackage.cs

New Types

public enum ConnectionMode
{
    None,        // No server running, watching for STDIO
    HttpServer,  // VS spawned Server.exe, HTTP/SSE mode
    StdioClient  // External Server.exe, STDIO mode
}

New Properties

public static ConnectionMode CurrentMode { get; private set; } = ConnectionMode.None;
public static IRpcClient? RpcClient { get; private set; }
public static IStdioPipeWatcher? PipeWatcher { get; private set; }

InitializeAsync Changes

// Initialize pipe watcher
PipeWatcher = _componentModel.GetService<IStdioPipeWatcher>();
RpcClient = _componentModel.GetService<IRpcClient>();

// If auto-start enabled: Start HTTP, pause watcher
if (Settings.AutoStart)
{
    CurrentMode = ConnectionMode.HttpServer;
    // ... start server (watcher stays paused)
}
else
{
    // Start watching for STDIO pipe
    PipeWatcher?.Start();
}

// Subscribe to pipe watcher events
PipeWatcher.PipeDetected += OnStdioPipeDetected;
PipeWatcher.Disconnected += OnStdioDisconnected;

Mode Transitions

• HTTP starts → Pause pipe watcher, set mode to HttpServer
• HTTP stops → Resume pipe watcher, set mode to None
• STDIO detected → Connect via RpcClient, set mode to StdioClient
• STDIO disconnects → Set mode to None, resume watching

Acceptance Criteria

• ConnectionMode enum added
• CurrentMode property added
• RpcClient and PipeWatcher properties added
• Mode transitions working correctly
• HTTP auto-start pauses pipe watcher
• STDIO detection triggers connection