fix: surface real network cause on Gitea issue creation failure (v0.51.4)

A thrown fetch error (DNS failure, connection refused, timeout) never
reached the res.ok branch, so its actual cause was lost — err.message
alone is often just "fetch failed" with the real reason nested in
err.cause. Now logs the full cause server-side and folds it into the
error returned to the admin support view's tooltip.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/lib/changelog.ts

@@ -1,5 +1,5 @@
 // Mirrors CHANGELOG.md at the repo root — update both together.
-export const APP_VERSION = "0.51.3";
+export const APP_VERSION = "0.51.4";
 
 export type ChangelogEntry = {
   version: string;
@@ -11,6 +11,13 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.51.4",
+    date: "2026-07-19 12:50",
+    fixed: [
+      "Gitea issue creation failures now log the real network-level cause server-side (DNS/connection/timeout, not just \"fetch failed\") and surface a more specific message in the admin support view's tooltip.",
+    ],
+  },
   {
     version: "0.51.3",
     date: "2026-07-19 12:35",