feat: Refactor service management scripts to use a unified dev script

- Added package.json to manage development scripts.
- Updated restart-services.ps1 to call the new dev script for starting services.
- Refactored start-admin.ps1, start-backend.ps1, start-frontend.ps1, and start-mcp.ps1 to utilize the dev script for starting respective services.
- Enhanced stop-services.ps1 to improve process termination logic by matching command patterns.

start-mcp.ps1

@@ -8,34 +8,7 @@ param(
 $ErrorActionPreference = "Stop"
 
 $repoRoot = Split-Path -Parent $MyInvocation.MyCommand.Path
-$mcpDir = Join-Path $repoRoot "mcp-server"
+$devScript = Join-Path $repoRoot "dev.ps1"
 
-if (-not (Test-Path $mcpDir)) {
-  throw "MCP server directory not found: $mcpDir"
-}
-
-Push-Location $mcpDir
-
-try {
-  if ($Install -or -not (Test-Path (Join-Path $mcpDir "node_modules"))) {
-    Write-Host "[mcp] Installing dependencies..." -ForegroundColor Cyan
-    npm install
-    if ($LASTEXITCODE -ne 0) {
-      throw "npm install failed"
-    }
-  }
-
-  $env:TERMI_MCP_API_KEY = $ApiKey
-  $env:TERMI_BACKEND_API_BASE = $BackendApiBase
-  $env:TERMI_MCP_PORT = "$Port"
-
-  Write-Host "[mcp] Backend API base set to $BackendApiBase" -ForegroundColor Cyan
-  Write-Host "[mcp] Starting MCP server on port $Port..." -ForegroundColor Green
-  npm run start
-  if ($LASTEXITCODE -ne 0) {
-    throw "npm run start failed"
-  }
-}
-finally {
-  Pop-Location
-}
+& $devScript -Only mcp -Install:$Install -McpApiKey $ApiKey -McpBackendApiBase $BackendApiBase -McpPort $Port
+exit $LASTEXITCODE