refactor: 拆分 gateway 单体为独立 crate，新增 systemd 部署方案

将 gateway 内部的 model-fetch、provider-transport、scheduler-core、
usage-runtime、video-tasks-core 模块提取为独立 crate；重构 gateway
内部模块结构（state/router/cache/data/query 等）；移除大量遗留模块
文件；新增 systemd 二进制部署骨架及相关文档；更新前端 usage 相关
API 和组件。

apps/aether-gateway/src/maintenance/runtime/runners.rs

@@ -1,7 +1,7 @@
 use tracing::info;
 
-use crate::gateway::gateway_data::GatewayDataState;
-use crate::gateway::{AppState, GatewayError};
+use crate::data::GatewayDataState;
+use crate::{AppState, GatewayError};
 
 use super::{
     cleanup_audit_logs_once, cleanup_expired_gemini_file_mappings_once,
@@ -16,7 +16,13 @@ pub(super) async fn run_audit_cleanup_once(
 ) -> Result<(), aether_data::DataLayerError> {
     let deleted = cleanup_audit_logs_once(data).await?;
     if deleted > 0 {
-        info!(deleted, "gateway deleted expired audit logs");
+        info!(
+            event_name = "audit_cleanup_completed",
+            log_type = "ops",
+            worker = "audit_cleanup",
+            deleted,
+            "gateway deleted expired audit logs"
+        );
     }
     Ok(())
 }
@@ -26,7 +32,13 @@ pub(super) async fn run_gemini_file_mapping_cleanup_once(
 ) -> Result<(), aether_data::DataLayerError> {
     let deleted = cleanup_expired_gemini_file_mappings_once(data).await?;
     if deleted > 0 {
-        info!(deleted, "gateway deleted expired gemini file mappings");
+        info!(
+            event_name = "gemini_file_mapping_cleanup_completed",
+            log_type = "ops",
+            worker = "gemini_file_mapping_cleanup",
+            deleted,
+            "gateway deleted expired gemini file mappings"
+        );
     }
     Ok(())
 }
@@ -37,6 +49,9 @@ pub(super) async fn run_db_maintenance_once(
     let summary = perform_db_maintenance_once(data).await?;
     if summary.attempted > 0 {
         info!(
+            event_name = "db_maintenance_completed",
+            log_type = "ops",
+            worker = "db_maintenance",
             attempted = summary.attempted,
             succeeded = summary.succeeded,
             failed = summary.attempted.saturating_sub(summary.succeeded),
@@ -51,6 +66,9 @@ pub(super) async fn run_wallet_daily_usage_aggregation_once(
 ) -> Result<(), aether_data::DataLayerError> {
     let summary = perform_wallet_daily_usage_aggregation_once(data).await?;
     info!(
+        event_name = "wallet_daily_usage_aggregation_completed",
+        log_type = "ops",
+        worker = "wallet_daily_usage_aggregation",
         billing_date = %summary.billing_date,
         billing_timezone = %summary.billing_timezone,
         wallets = summary.aggregated_wallets,
@@ -68,6 +86,9 @@ pub(super) async fn run_stats_aggregation_once(
     };
 
     info!(
+        event_name = "stats_daily_aggregation_completed",
+        log_type = "ops",
+        worker = "stats_daily_aggregation",
         day_start_utc = %summary.day_start_utc,
         total_requests = summary.total_requests,
         model_rows = summary.model_rows,
@@ -91,6 +112,9 @@ pub(super) async fn run_usage_cleanup_once(
         || summary.records_deleted > 0
     {
         info!(
+            event_name = "usage_cleanup_completed",
+            log_type = "ops",
+            worker = "usage_cleanup",
             body_compressed = summary.body_compressed,
             body_cleaned = summary.body_cleaned,
             header_cleaned = summary.header_cleaned,
@@ -108,6 +132,9 @@ pub(super) fn run_pool_monitor_once(data: &GatewayDataState) {
     };
 
     info!(
+        event_name = "postgres_pool_sampled",
+        log_type = "ops",
+        worker = "pool_monitor",
         checked_out = summary.checked_out,
         pool_size = summary.pool_size,
         idle = summary.idle,
@@ -123,6 +150,9 @@ pub(super) async fn run_pending_cleanup_once(
     let summary = cleanup_stale_pending_requests_once(data).await?;
     if summary.failed > 0 || summary.recovered > 0 {
         info!(
+            event_name = "pending_cleanup_completed",
+            log_type = "ops",
+            worker = "pending_cleanup",
             failed = summary.failed,
             recovered = summary.recovered,
             "gateway cleaned stale pending and streaming requests"
@@ -139,6 +169,9 @@ pub(super) async fn run_stats_hourly_aggregation_once(
     };
 
     info!(
+        event_name = "stats_hourly_aggregation_completed",
+        log_type = "ops",
+        worker = "stats_hourly_aggregation",
         hour_utc = %summary.hour_utc,
         total_requests = summary.total_requests,
         user_rows = summary.user_rows,
@@ -153,6 +186,9 @@ pub(super) async fn run_provider_checkin_once(state: &AppState) -> Result<(), Ga
     let summary = perform_provider_checkin_once(state).await?;
     if summary.attempted > 0 {
         info!(
+            event_name = "provider_checkin_completed",
+            log_type = "ops",
+            worker = "provider_checkin",
             attempted = summary.attempted,
             succeeded = summary.succeeded,
             failed = summary.failed,