docs: spell out Gitea integration setup in admin Settings UI (v0.51.3)

GITEA_URL/GITEA_REPO format and the exact token scope needed (issue
read+write only) were only in the commit message and CLAUDE session —
now visible right above the fields admins are filling in.

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 = "0.51.2";
+export const APP_VERSION = "0.51.3";
 
 export type ChangelogEntry = {
   version: string;
@@ -11,6 +11,13 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.51.3",
+    date: "2026-07-19 12:35",
+    fixed: [
+      "Admin Settings' Gitea Integration section now spells out exactly what each field expects and what token scope to grant, instead of a one-line hint.",
+    ],
+  },
   {
     version: "0.51.2",
     date: "2026-07-19 12:20",