Add validation and sanitization for SocialLink objects

Introduce validation for each SocialLink in SettingsController.
Parse JsonData into SocialLink array and check Name, Icon, and Url.
Add errors to ModelState and return BadRequest for invalid data.
Validate Url as absolute URI and sanitize using Helper.SterilizeLink.
Assign validated SocialLinks to blogConfig.SocialLinkSettings.

src/Moonglade.Web/Controllers/SettingsController.cs

@@ -163,10 +163,43 @@ public async Task<IActionResult> SocialLink(SocialLinkSettingsJsonModel model)
             return BadRequest(ModelState.CombineErrorMessages());
         }
 
+        var links = model.JsonData.FromJson<SocialLink[]>();
+
+        // Check each link, if any link is invalid, return BadRequest
+        foreach (var link in links)
+        {
+            if (string.IsNullOrWhiteSpace(link.Name))
+            {
+                ModelState.AddModelError($"{nameof(Moonglade.Configuration.SocialLink)}.{nameof(Moonglade.Configuration.SocialLink.Name)}", "Name is required");
+                return BadRequest(ModelState.CombineErrorMessages());
+            }
+
+            if (string.IsNullOrWhiteSpace(link.Icon))
+            {
+                ModelState.AddModelError($"{nameof(Moonglade.Configuration.SocialLink)}.{nameof(Moonglade.Configuration.SocialLink.Icon)}", "Icon is required");
+                return BadRequest(ModelState.CombineErrorMessages());
+            }
+
+            if (string.IsNullOrWhiteSpace(link.Url))
+            {
+                ModelState.AddModelError($"{nameof(Moonglade.Configuration.SocialLink)}.{nameof(Moonglade.Configuration.SocialLink.Url)}", "Url is required");
+                return BadRequest(ModelState.CombineErrorMessages());
+            }
+
+            if (!Uri.TryCreate(link.Url, UriKind.Absolute, out _))
+            {
+                ModelState.AddModelError($"{nameof(Moonglade.Configuration.SocialLink)}.{nameof(Moonglade.Configuration.SocialLink.Url)}", "Url is invalid");
+                return BadRequest(ModelState.CombineErrorMessages());
+            }
+
+            // Sterilize
+            link.Url = Helper.SterilizeLink(link.Url);
+        }
+
         blogConfig.SocialLinkSettings = new()
         {
             IsEnabled = model.IsEnabled,
-            Links = model.JsonData.FromJson<SocialLink[]>()
+            Links = links
         };
 
         await SaveConfigAsync(blogConfig.SocialLinkSettings);