接入AGC后台模型目录与对话模型选择

新增后台 AGC 模型目录、别名、启停和默认项管理

客户端设置页恢复原状，对话框右下角按别名选择模型

服务端按稳定模型标识映射并校验实际模型白名单

修复 AGC 配套后端端口漂移、启动等待和 SpacetimeDB 版本检查

补充迁移、文档、启动与模型选择测试

apps/admin-web/src/styles/admin.css

@@ -3093,5 +3093,54 @@ button:disabled {
   background: var(--admin-surface, #fff);
 }
 .admin-detail-modal__panel header,
-.admin-detail-modal__actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
-.admin-detail-modal__panel pre { max-height: 360px; overflow: auto; white-space: pre-wrap; background: #f8fafc; padding: 12px; border-radius: 8px; }
+.admin-detail-modal__actions {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+.admin-detail-modal__panel pre {
+  max-height: 360px;
+  overflow: auto;
+  white-space: pre-wrap;
+  background: #f8fafc;
+  padding: 12px;
+  border-radius: 8px;
+}
+.admin-agc-models {
+  min-width: 0;
+}
+.admin-agc-models > header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+.admin-agc-models > header > div {
+  display: flex;
+  gap: 8px;
+}
+.admin-agc-models button {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 6px;
+  min-height: 32px;
+}
+.admin-agc-models-table {
+  overflow-x: auto;
+}
+.admin-agc-models table {
+  width: 100%;
+  border-collapse: collapse;
+}
+.admin-agc-models th,
+.admin-agc-models td {
+  padding: 8px;
+  text-align: left;
+}
+.admin-agc-models td input:not([type]) {
+  min-width: 150px;
+  width: 100%;
+  box-sizing: border-box;
+}