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-contracts/src/repository/billing/mod.rs

@@ -0,0 +1,7 @@
+mod types;
+
+pub use types::{
+    AdminBillingCollectorRecord, AdminBillingCollectorWriteInput, AdminBillingPresetApplyResult,
+    AdminBillingRuleRecord, AdminBillingRuleWriteInput, BillingReadRepository,
+    StoredBillingModelContext,
+};

crates/aether-data-contracts/src/repository/billing/types.rs

@@ -0,0 +1,153 @@
+use async_trait::async_trait;
+use serde_json::Value;
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct StoredBillingModelContext {
+    pub provider_id: String,
+    pub provider_billing_type: Option<String>,
+    pub provider_api_key_id: Option<String>,
+    pub provider_api_key_rate_multipliers: Option<Value>,
+    pub provider_api_key_cache_ttl_minutes: Option<i64>,
+    pub global_model_id: String,
+    pub global_model_name: String,
+    pub global_model_config: Option<Value>,
+    pub default_price_per_request: Option<f64>,
+    pub default_tiered_pricing: Option<Value>,
+    pub model_id: Option<String>,
+    pub model_provider_model_name: Option<String>,
+    pub model_config: Option<Value>,
+    pub model_price_per_request: Option<f64>,
+    pub model_tiered_pricing: Option<Value>,
+}
+
+impl StoredBillingModelContext {
+    #[allow(clippy::too_many_arguments)]
+    pub fn new(
+        provider_id: String,
+        provider_billing_type: Option<String>,
+        provider_api_key_id: Option<String>,
+        provider_api_key_rate_multipliers: Option<Value>,
+        provider_api_key_cache_ttl_minutes: Option<i64>,
+        global_model_id: String,
+        global_model_name: String,
+        global_model_config: Option<Value>,
+        default_price_per_request: Option<f64>,
+        default_tiered_pricing: Option<Value>,
+        model_id: Option<String>,
+        model_provider_model_name: Option<String>,
+        model_config: Option<Value>,
+        model_price_per_request: Option<f64>,
+        model_tiered_pricing: Option<Value>,
+    ) -> Result<Self, crate::DataLayerError> {
+        if provider_id.trim().is_empty() {
+            return Err(crate::DataLayerError::UnexpectedValue(
+                "billing.provider_id is empty".to_string(),
+            ));
+        }
+        if global_model_id.trim().is_empty() {
+            return Err(crate::DataLayerError::UnexpectedValue(
+                "billing.global_model_id is empty".to_string(),
+            ));
+        }
+        if global_model_name.trim().is_empty() {
+            return Err(crate::DataLayerError::UnexpectedValue(
+                "billing.global_model_name is empty".to_string(),
+            ));
+        }
+        Ok(Self {
+            provider_id,
+            provider_billing_type,
+            provider_api_key_id,
+            provider_api_key_rate_multipliers,
+            provider_api_key_cache_ttl_minutes,
+            global_model_id,
+            global_model_name,
+            global_model_config,
+            default_price_per_request,
+            default_tiered_pricing,
+            model_id,
+            model_provider_model_name,
+            model_config,
+            model_price_per_request,
+            model_tiered_pricing,
+        })
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct AdminBillingRuleRecord {
+    pub id: String,
+    pub name: String,
+    pub task_type: String,
+    pub global_model_id: Option<String>,
+    pub model_id: Option<String>,
+    pub expression: String,
+    pub variables: Value,
+    pub dimension_mappings: Value,
+    pub is_enabled: bool,
+    pub created_at_unix_secs: u64,
+    pub updated_at_unix_secs: u64,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct AdminBillingRuleWriteInput {
+    pub name: String,
+    pub task_type: String,
+    pub global_model_id: Option<String>,
+    pub model_id: Option<String>,
+    pub expression: String,
+    pub variables: Value,
+    pub dimension_mappings: Value,
+    pub is_enabled: bool,
+}
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct AdminBillingCollectorRecord {
+    pub id: String,
+    pub api_format: String,
+    pub task_type: String,
+    pub dimension_name: String,
+    pub source_type: String,
+    pub source_path: Option<String>,
+    pub value_type: String,
+    pub transform_expression: Option<String>,
+    pub default_value: Option<String>,
+    pub priority: i32,
+    pub is_enabled: bool,
+    pub created_at_unix_secs: u64,
+    pub updated_at_unix_secs: u64,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct AdminBillingCollectorWriteInput {
+    pub api_format: String,
+    pub task_type: String,
+    pub dimension_name: String,
+    pub source_type: String,
+    pub source_path: Option<String>,
+    pub value_type: String,
+    pub transform_expression: Option<String>,
+    pub default_value: Option<String>,
+    pub priority: i32,
+    pub is_enabled: bool,
+}
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct AdminBillingPresetApplyResult {
+    pub preset: String,
+    pub mode: String,
+    pub created: u64,
+    pub updated: u64,
+    pub skipped: u64,
+    pub errors: Vec<String>,
+}
+
+#[async_trait]
+pub trait BillingReadRepository: Send + Sync {
+    async fn find_model_context(
+        &self,
+        provider_id: &str,
+        provider_api_key_id: Option<&str>,
+        global_model_name: &str,
+    ) -> Result<Option<StoredBillingModelContext>, crate::DataLayerError>;
+}