refactor: 大规模模块拆分与代码精简，新增 ai-pipeline/data-contracts 独立 crate

- 新增 aether-ai-pipeline 和 aether-data-contracts crate，将 pipeline 逻辑与数据契约从 gateway 中解耦
- 重构 admin handlers：拆分单体模块为 auth/billing/endpoint/features/model/observability/provider/system 等独立子模块
- 合并 chat/cli 重复代码路径：精简 conversion、finalize、planner 中的 sync/chat/cli 分支
- 重构 scheduler/executor/data 层，引入 facade 模式降低模块间耦合
- 移除冗余的 intent 模块，将 plan_fallback/policy/stream_path/sync_path 迁移至 executor
- 前端适配：调整 admin API 调用和 provider 模型测试对话框

apps/aether-gateway/src/tests/control/admin/models/external.rs

@@ -11,6 +11,27 @@ use crate::constants::{
     TRUSTED_ADMIN_USER_ROLE_HEADER,
 };
 
+struct TestEnvVarGuard {
+    key: &'static str,
+    previous: Option<String>,
+}
+
+impl Drop for TestEnvVarGuard {
+    fn drop(&mut self) {
+        if let Some(previous) = self.previous.as_deref() {
+            std::env::set_var(self.key, previous);
+        } else {
+            std::env::remove_var(self.key);
+        }
+    }
+}
+
+fn set_test_env_var(key: &'static str, value: &str) -> TestEnvVarGuard {
+    let previous = std::env::var(key).ok();
+    std::env::set_var(key, value);
+    TestEnvVarGuard { key, previous }
+}
+
 #[tokio::test]
 async fn gateway_handles_admin_external_models_locally_with_trusted_admin_principal() {
     let upstream_hits = Arc::new(Mutex::new(0usize));
@@ -27,6 +48,29 @@ async fn gateway_handles_admin_external_models_locally_with_trusted_admin_princi
     );
 
     let (upstream_url, upstream_handle) = start_server(upstream).await;
+    let external_source = Router::new().route(
+        "/api.json",
+        any(|_request: Request| async move {
+            (
+                StatusCode::OK,
+                axum::Json(serde_json::json!({
+                    "openai": {
+                        "name": "OpenAI",
+                        "models": {
+                            "gpt-5": {
+                                "name": "GPT-5"
+                            }
+                        }
+                    }
+                })),
+            )
+        }),
+    );
+    let (external_source_url, external_source_handle) = start_server(external_source).await;
+    let _guard = set_test_env_var(
+        "AETHER_GATEWAY_EXTERNAL_MODELS_URL",
+        &format!("{external_source_url}/api.json"),
+    );
     let gateway = build_router_with_state(AppState::new().expect("gateway should build"));
     let (gateway_url, gateway_handle) = start_server(gateway).await;
 
@@ -40,15 +84,17 @@ async fn gateway_handles_admin_external_models_locally_with_trusted_admin_princi
         .await
         .expect("request should succeed");
 
-    assert_eq!(response.status(), StatusCode::SERVICE_UNAVAILABLE);
+    assert_eq!(response.status(), StatusCode::OK);
     let payload: serde_json::Value = response.json().await.expect("json body should parse");
+    assert_eq!(payload["openai"]["official"], serde_json::json!(true));
     assert_eq!(
-        payload["detail"],
-        "External models catalog requires Rust admin backend"
+        payload["openai"]["models"]["gpt-5"]["name"],
+        serde_json::json!("GPT-5")
     );
     assert_eq!(*upstream_hits.lock().expect("mutex should lock"), 0);
 
     gateway_handle.abort();
+    external_source_handle.abort();
     upstream_handle.abort();
 }
 

apps/aether-gateway/src/tests/control/admin/models/global.rs

@@ -1,9 +1,10 @@
 use std::sync::{Arc, Mutex};
 
-use aether_data::repository::global_models::{
-    AdminProviderModelListQuery, GlobalModelReadRepository, InMemoryGlobalModelReadRepository,
-};
+use aether_data::repository::global_models::InMemoryGlobalModelReadRepository;
 use aether_data::repository::provider_catalog::InMemoryProviderCatalogReadRepository;
+use aether_data_contracts::repository::global_models::{
+    AdminProviderModelListQuery, GlobalModelReadRepository,
+};
 use axum::body::Body;
 use axum::routing::any;
 use axum::{extract::Request, Router};

apps/aether-gateway/src/tests/control/admin/models/provider.rs

@@ -1,10 +1,12 @@
 use std::sync::{Arc, Mutex};
 
-use aether_data::repository::global_models::{
-    AdminProviderModelListQuery, GlobalModelReadRepository, InMemoryGlobalModelReadRepository,
-};
+use aether_data::repository::global_models::InMemoryGlobalModelReadRepository;
 use aether_data::repository::provider_catalog::InMemoryProviderCatalogReadRepository;
 use aether_data::repository::quota::InMemoryProviderQuotaRepository;
+use aether_data_contracts::repository::{
+    global_models::{AdminProviderModelListQuery, GlobalModelReadRepository},
+    quota::StoredProviderQuotaSnapshot,
+};
 use axum::body::Body;
 use axum::routing::any;
 use axum::{extract::Request, Router};