feat: CI registers release manifests without a token; the panel verifies the CI signature instead [CI]

backend/src/MoShiro.Backend.Api/Admin/BuildEndpoints.cs

@@ -45,6 +45,31 @@ public static class BuildEndpoints
             .Requires(Capability.ReleasePublish);
     }
 
+    /// <summary>
+    /// CI 登记清单的入口，<b>不需要令牌</b>：请求里的清单必须带有效的 CI 发布签名（用 Backend 内嵌的发布公钥验）才收下。
+    /// 这样登记不依赖面板里的任何凭证（清库、重装、还没有 passkey 的时候照常工作），也没有一把能被偷的长期令牌；
+    /// 旧清单重放由 <c>seq</c> 递增挡住，节点的更新器还会用本机公钥再验一次。
+    /// </summary>
+    public static void MapOffer(IEndpointRouteBuilder app)
+    {
+        app.MapPost("/api/release/offer", OfferReleaseAsync)
+            .Api("release_offer", "Register a release manifest that carries a valid CI signature (no token needed)", "release")
+            .Returns<ReleaseDto>(StatusCodes.Status201Created).ProducesProblems(400, 403, 409);
+    }
+
+    private static async Task<IResult> OfferReleaseAsync(HttpContext http, ReleaseService releases, PublishReleaseRequest request)
+    {
+        string manifest = request.Manifest ?? "";
+        string signature = request.Signature ?? "";
+        if (manifest.Length is 0 or > ReleaseService.MaxManifestBytes || signature.Length is 0 or > ReleaseService.MaxSignatureBytes
+            || !ReleaseSignature.Verify(InstallScripts.ReleaseKey(), manifest, signature))
+        {
+            return Problems.Create(http, MoShiroErrors.Forbidden, "the manifest does not carry a valid release signature");
+        }
+
+        return await PublishReleaseAsync(http, releases, request);
+    }
+
     private static async Task<IResult> GetAsync(HttpContext http, NodeInfoService nodes, ReleaseService releases, BackendUpdates backendUpdates, CancellationToken ct)
     {
         var items = (await nodes.ListAsync(ct))