feat!: genesis-pinned operator set, server identity with an encrypted control link, key-less join codes; release key continuity

Join codes need no passkey touch and carry only public values (genesis
fingerprint, owner credentials, installer hashes). Nodes pin the genesis and
owners at enrollment and only follow passkey-signed operator set versions.
The panel's server key is listed in the set; pinned nodes require its
signature and run the control link under AES-256-GCM. Password sessions carry
no capabilities. The updater adopts a next_key from a signed manifest.

Bump version to 0.2.0. [CI SKIP]

backend/src/MoShiro.Backend.Api/OpsEndpoints.cs

@@ -19,12 +19,12 @@ public static class OpsEndpoints
         app.MapGet("/metrics", MetricsAsync)
             .Api("metrics_get", "Prometheus metrics (requires ops.metrics)", Tag)
             .Produces(StatusCodes.Status200OK, contentType: "text/plain").ProducesProblems(401, 403);
-        // 一行安装：curl -fsSL 'https://panel/install?code=…' | bash（macOS 用 zsh），irm 'https://panel/install.ps1?code=…' | iex（Windows）。
-        // Agent 和 Probe 是同一份脚本，角色、网关和镜像由一次性代码决定；代码不能用就是 404。
-        app.MapGet("/install", (HttpContext http, JoinTokenService tokens, BackendOptions options, string? code) => InstallAsync(http, tokens, options, code, "install.sh", "text/x-shellscript"))
-            .Api("install_sh", "One-line installer for Linux and macOS nodes (agent or probe, decided by the code)", Tag)
-            .Produces(StatusCodes.Status200OK, contentType: "text/x-shellscript").ProducesProblems(404);
-        app.MapGet("/install.sh", (HttpContext http, JoinTokenService tokens, BackendOptions options, string? code) => InstallAsync(http, tokens, options, code, "install.sh", "text/x-shellscript"))
+        // 一行安装：面板给的命令先下载这份静态脚本、核对 SHA-256，再用环境变量里的面板地址、角色和一次性代码执行。
+        // 脚本不含任何一次性的值，所以不需要代码，也可以直接拿去和发布页公布的哈希核对。
+        app.MapGet("/install", (HttpContext http) => Static(http, InstallScripts.Sh, "text/x-shellscript"))
+            .Api("install_sh", "The static one-line installer for Linux and macOS nodes (same bytes for everyone; its SHA-256 is published with each release)", Tag)
+            .Produces(StatusCodes.Status200OK, contentType: "text/x-shellscript");
+        app.MapGet("/install.sh", (HttpContext http) => Static(http, InstallScripts.Sh, "text/x-shellscript"))
             .ExcludeFromDescription();
         // 脚本要装的版本：CI 签名的发布清单（原样的字节）和签名。脚本用内置的发布公钥验签，再按清单里的 digest 拉镜像。
         app.MapGet("/install/manifest", (HttpContext http, JoinTokenService tokens, ReleaseService releases, BackendOptions options, string? code) => ManifestAsync(http, tokens, releases, options, code, signature: false))
@@ -33,9 +33,9 @@ public static class OpsEndpoints
         app.MapGet("/install/manifest.sig", (HttpContext http, JoinTokenService tokens, ReleaseService releases, BackendOptions options, string? code) => ManifestAsync(http, tokens, releases, options, code, signature: true))
             .Api("install_manifest_signature", "Base64 DER ECDSA P-256 signature of the manifest", Tag)
             .Produces(StatusCodes.Status200OK, contentType: "text/plain").ProducesProblems(404);
-        app.MapGet("/install.ps1", (HttpContext http, JoinTokenService tokens, BackendOptions options, string? code) => InstallAsync(http, tokens, options, code, "install.ps1", "text/plain"))
-            .Api("install_ps1", "One-line installer for Windows nodes (agent or probe, decided by the code)", Tag)
-            .Produces(StatusCodes.Status200OK, contentType: "text/plain").ProducesProblems(404);
+        app.MapGet("/install.ps1", (HttpContext http) => Static(http, InstallScripts.Ps1, "text/plain"))
+            .Api("install_ps1", "The static one-line installer for Windows nodes (same bytes for everyone; its SHA-256 is published with each release)", Tag)
+            .Produces(StatusCodes.Status200OK, contentType: "text/plain");
     }
 
     private static async Task<IResult> ManifestAsync(HttpContext http, JoinTokenService tokens, ReleaseService releases, BackendOptions options, string? code, bool signature)
@@ -52,18 +52,10 @@ public static class OpsEndpoints
         return signature ? TypedResults.Text(offer.Signature, "text/plain; charset=utf-8") : TypedResults.Text(offer.Manifest, "application/json; charset=utf-8");
     }
 
-    private static async Task<IResult> InstallAsync(HttpContext http, JoinTokenService tokens, BackendOptions options, string? code, string resource, string contentType)
+    private static Microsoft.AspNetCore.Http.HttpResults.ContentHttpResult Static(HttpContext http, string resource, string contentType)
     {
-        string baseUrl = options.PublicUrl ?? $"{http.Request.Scheme}://{http.Request.Host}";
-        InstallTarget? target = string.IsNullOrEmpty(code) ? null : await tokens.ResolveInstallAsync(code, baseUrl, http.RequestAborted);
-        if (target is null)
-        {
-            return Problems.Create(http, MoShiroErrors.NotFound, "the install code is invalid, expired or already used");
-        }
-
-        string script = InstallScripts.Render(resource, target);
         http.Response.Headers.CacheControl = "no-store";
-        return TypedResults.Text(script, contentType + "; charset=utf-8");
+        return TypedResults.Text(InstallScripts.Script(resource), contentType + "; charset=utf-8");
     }
 
     private static async Task<IResult> HealthAsync(HttpContext http, OpsService ops)