Implement chat rendering and message handling with colored segments

src/EchoHub.Server/Controllers/FilesController.cs

@@ -0,0 +1,32 @@
+using EchoHub.Server.Services;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EchoHub.Server.Controllers;
+
+[ApiController]
+[Route("api/files")]
+public class FilesController(FileStorageService fileStorage) : ControllerBase
+{
+    [HttpGet("{fileId}")]
+    public IActionResult GetFile(string fileId)
+    {
+        var filePath = fileStorage.GetFilePath(fileId);
+
+        if (filePath is null)
+            return NotFound(new { Error = "File not found." });
+
+        var contentType = Path.GetExtension(filePath).ToLowerInvariant() switch
+        {
+            ".jpg" or ".jpeg" => "image/jpeg",
+            ".png" => "image/png",
+            ".gif" => "image/gif",
+            ".webp" => "image/webp",
+            ".pdf" => "application/pdf",
+            ".txt" => "text/plain",
+            _ => "application/octet-stream"
+        };
+
+        var fileName = Path.GetFileName(filePath);
+        return PhysicalFile(filePath, contentType, fileName);
+    }
+}