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

crates/aether-data/src/postgres/lease.rs

@@ -1,3 +1,4 @@
+use crate::error::SqlxResultExt;
 use crate::postgres::{DatabaseRecordId, PostgresTransactionOptions, PostgresTransactionRunner};
 use crate::DataLayerError;
 use futures_util::FutureExt;
@@ -108,7 +109,8 @@ impl PostgresLeaseRunner {
                         .bind(owner)
                         .bind(lease_ms)
                         .fetch_all(&mut **tx)
-                        .await?;
+                        .await
+                        .map_postgres_err()?;
                     Ok(rows.into_iter().map(DatabaseRecordId).collect())
                 }
                 .boxed()
@@ -142,7 +144,8 @@ impl PostgresLeaseRunner {
                         .bind(ids)
                         .bind(owner)
                         .fetch_all(&mut **tx)
-                        .await?;
+                        .await
+                        .map_postgres_err()?;
                     Ok(rows.into_iter().map(DatabaseRecordId).collect())
                 }
                 .boxed()
@@ -186,7 +189,8 @@ impl PostgresLeaseRunner {
                         .bind(owner)
                         .bind(lease_ms)
                         .fetch_all(&mut **tx)
-                        .await?;
+                        .await
+                        .map_postgres_err()?;
                     Ok(rows.into_iter().map(DatabaseRecordId).collect())
                 }
                 .boxed()

crates/aether-data/src/postgres/tx.rs

@@ -1,6 +1,7 @@
 use futures_util::future::BoxFuture;
 use sqlx::{Postgres, Transaction};
 
+use crate::error::{postgres_error, SqlxResultExt};
 use crate::postgres::PostgresPool;
 use crate::DataLayerError;
 
@@ -70,9 +71,12 @@ impl PostgresTransactionRunner {
     ) -> Result<PostgresTransaction, DataLayerError> {
         options.validate()?;
 
-        let mut tx = self.pool.begin().await?;
+        let mut tx = self.pool.begin().await.map_postgres_err()?;
         for statement in build_transaction_setup_statements(options) {
-            sqlx::query(statement.as_str()).execute(&mut *tx).await?;
+            sqlx::query(statement.as_str())
+                .execute(&mut *tx)
+                .await
+                .map_postgres_err()?;
         }
         Ok(tx)
     }
@@ -90,7 +94,7 @@ impl PostgresTransactionRunner {
         let mut tx = self.begin(options).await?;
         match f(&mut tx).await {
             Ok(value) => {
-                tx.commit().await?;
+                tx.commit().await.map_err(postgres_error)?;
                 Ok(value)
             }
             Err(err) => {