feat(gitea): add domain model classes, helpers, and refactor GiteaClient internals; expand README with usage and docs

ts/gitea.classes.secret.ts

@@ -0,0 +1,18 @@
+import type { IGiteaSecret } from './gitea.interfaces.js';
+
+export class GiteaSecret {
+  public readonly name: string;
+  public readonly createdAt: string;
+
+  constructor(raw: IGiteaSecret) {
+    this.name = raw.name || '';
+    this.createdAt = raw.created_at || '';
+  }
+
+  toJSON(): IGiteaSecret {
+    return {
+      name: this.name,
+      created_at: this.createdAt,
+    };
+  }
+}