Add screenshots and update gitignore for alpha release

- Fixed gitignore to allow Screenshots/*.png files
- Added all screenshots for README documentation
- Fixed gitignore to be less restrictive with image files
- Includes dashboard, agent, updates, and docker screenshots

aggregator-server/internal/api/middleware/cors.go

@@ -0,0 +1,26 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+// CORSMiddleware handles Cross-Origin Resource Sharing
+func CORSMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		c.Header("Access-Control-Allow-Origin", "http://localhost:3000")
+		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+		c.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
+		c.Header("Access-Control-Expose-Headers", "Content-Length")
+		c.Header("Access-Control-Allow-Credentials", "true")
+
+		// Handle preflight requests
+		if c.Request.Method == "OPTIONS" {
+			c.AbortWithStatus(http.StatusNoContent)
+			return
+		}
+
+		c.Next()
+	}
+}