Every credential provider says whether it still holds a consumer

holds() for postgres, mssql, mongodb, minio, lavinmq, mosquitto, mailu
and gitea, so the harness makes again a login the backend lost (hq issue
120). Each checks the mesh's password as the consumer presents it, or
compares it read-only, and returns false only when the backend says the
credential is absent or wrong; an unreachable backend throws.

modules/gitea/client.ts

@@ -433,6 +433,29 @@ export class GiteaAdmin {
     GiteaAdmin.fail(`/teams/${teamId}/members/${username}`, res);
   }
 
+  /**
+   * Whether a consumer's user logs in with exactly this password and is still a member of the
+   * package team. Read-only: the password is checked as the consumer presents it, basic auth on the
+   * API, and membership through the admin API. `false` for a refused login or a missing member; any
+   * other answer rejects (novox/hq issue 120).
+   */
+  async holdsTeamMember(org: string, team: string, username: string, password: string): Promise<boolean> {
+    const me = await fetch(`${this.baseUrl}/api/v1/user`, {
+      headers: { Authorization: "Basic " + Buffer.from(`${username}:${password}`).toString("base64") },
+    });
+    if (me.status === 401 || me.status === 403) return false;
+    if (me.status !== 200) throw new Error(`Gitea GET /user as ${username}: ${me.status}`);
+    const teams = await this.request(`/orgs/${encodeURIComponent(org)}/teams`);
+    if (teams.status === 404) return false;
+    if (teams.status !== 200) GiteaAdmin.fail(`/orgs/${org}/teams`, teams);
+    const found = (teams.body as { id: number; name: string }[]).find((t) => t.name === team);
+    if (!found) return false;
+    const member = await this.request(`/teams/${found.id}/members/${encodeURIComponent(username)}`);
+    if (member.status === 200 || member.status === 204) return true;
+    if (member.status === 404) return false;
+    GiteaAdmin.fail(`/teams/${found.id}/members/${username}`, member);
+  }
+
   /** Delete a user, purging what they own. A 404 means the mesh already withdrew them — success, not
    *  an error, so a re-run of remove is safe. */
   async deleteUser(username: string): Promise<void> {