chore(ver): bump version to 1.8.3 and clean solution

- Bump version to 1.8.3
- Add 1.8.3 changelog
- Migrate to .slnx
- Cleanup solution

changelog/1.8.3.json

@@ -0,0 +1,46 @@
+{
+  "version": "1.8.3",
+  "date": "2026-03-13",
+  "changes": [
+    {
+      "type": "NEW",
+      "text": "Introduced a redesigned update system with a custom update dialog and integrated changelog viewer",
+      "link": "https://github.com/achiez/NebulaAuth-Steam-Desktop-Authenticator-by-Achies/pull/19"
+    },
+    {
+      "type": "NEW",
+      "text": "Added support for importing SDA-encrypted mafiles with automatic manifest detection",
+      "link": "https://github.com/achiez/NebulaAuth-Steam-Desktop-Authenticator-by-Achies/pull/17"
+    },
+    {
+      "type": "NEW",
+      "text": "Grouped market confirmations can now be expanded to reveal individual items",
+      "link": "https://github.com/achiez/NebulaAuth-Steam-Desktop-Authenticator-by-Achies/pull/18"
+    },
+    {
+      "type": "SECURITY",
+      "text": "Added SHA256 checksum verification for downloaded update packages"
+    },
+    {
+      "type": "IMPROVEMENT",
+      "text": "Export feature now trims input automatically to prevent issues caused by invisible characters or extra spaces"
+    },
+    {
+      "type": "IMPROVEMENT",
+      "text": "Improved update experience with 'Remind later' and 'Skip version' options"
+    },
+    {
+      "type": "IMPROVEMENT",
+      "text": "Added visual update indicator and manual 'Check for updates' action"
+    },
+    {
+      "type": "IMPROVEMENT",
+      "text": "Expanded localization support with Spanish, Turkish and Kazakh languages"
+    },
+    {
+      "type": "INFO",
+      "text": "Read the full release notes for NebulaAuth 1.8.3",
+      "link": "https://teletype.in/@achies_raw/o-RDwZKZkAU"
+    }
+  ]
+}