refactor: 移除 Python upstream 依赖，清理全部 legacy/Python 兼容层

- 移除 upstream_base_url 参数及 AETHER_GATEWAY_UPSTREAM 环境变量，gateway 不再需要指向 Python 宿主
- 删除所有 LEGACY_*/PYTHON_* 常量、路由组、header 定义及 sunset/phaseout 机制
- 将 legacy_gateway_bridge 重命名为 internal_gateway，executor 相关命名统一为 execution_runtime
- dev.sh 新增 Postgres/Redis 预检查，移除 upstream 相关启动参数和提示
- 新增 ai_public 路由处理器
- 全量适配 handler、test、state、control 等模块的命名和接口变更

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

@@ -1,4 +1,24 @@
-use super::*;
+use std::collections::HashMap;
+
+use chrono::{DateTime, Utc};
+use sqlx::Row;
+use uuid::Uuid;
+
+use crate::gateway::gateway_data::GatewayDataState;
+
+use super::{
+    stats_aggregation_target_day, system_config_bool, PercentileSummary, StatsAggregationSummary,
+    DELETE_STATS_DAILY_ERRORS_FOR_DATE_SQL, INSERT_STATS_DAILY_ERROR_SQL, INSERT_STATS_SUMMARY_SQL,
+    SELECT_ACTIVE_USER_IDS_SQL, SELECT_EXISTING_STATS_SUMMARY_ID_SQL,
+    SELECT_STATS_DAILY_AGGREGATE_SQL, SELECT_STATS_DAILY_API_KEY_AGGREGATES_SQL,
+    SELECT_STATS_DAILY_ERROR_AGGREGATES_SQL, SELECT_STATS_DAILY_FALLBACK_COUNT_SQL,
+    SELECT_STATS_DAILY_FIRST_BYTE_PERCENTILES_SQL, SELECT_STATS_DAILY_MODEL_AGGREGATES_SQL,
+    SELECT_STATS_DAILY_PROVIDER_AGGREGATES_SQL, SELECT_STATS_DAILY_RESPONSE_TIME_PERCENTILES_SQL,
+    SELECT_STATS_SUMMARY_ENTITY_COUNTS_SQL, SELECT_STATS_SUMMARY_TOTALS_SQL,
+    SELECT_STATS_USER_DAILY_AGGREGATES_SQL, UPDATE_STATS_SUMMARY_SQL,
+    UPSERT_STATS_DAILY_API_KEY_SQL, UPSERT_STATS_DAILY_MODEL_SQL, UPSERT_STATS_DAILY_PROVIDER_SQL,
+    UPSERT_STATS_DAILY_SQL, UPSERT_STATS_USER_DAILY_SQL,
+};
 
 pub(super) async fn perform_stats_aggregation_once(
     data: &GatewayDataState,