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/state/app.rs

@@ -0,0 +1,114 @@
+use std::collections::HashMap;
+use std::sync::Arc;
+use std::sync::Mutex as StdMutex;
+
+use aether_runtime::{ConcurrencyGate, DistributedConcurrencyGate};
+
+use super::super::async_task::{VideoTaskPollerConfig, VideoTaskService};
+use super::super::fallback_metrics;
+use super::super::cache::{
+    AuthApiKeyLastUsedCache, AuthContextCache, DirectPlanBypassCache, SchedulerAffinityCache,
+};
+use super::super::data::GatewayDataState;
+use super::super::rate_limit::FrontdoorUserRpmLimiter;
+use super::super::{provider_transport, usage};
+use super::{
+    AdminBillingCollectorRecord, AdminBillingRuleRecord, AdminPaymentCallbackRecord,
+    AdminWalletPaymentOrderRecord, AdminWalletRefundRecord, AdminWalletTransactionRecord,
+    CachedProviderTransportSnapshot, FrontdoorCorsConfig, LocalExecutionRuntimeMissDiagnostic,
+    LocalProviderDeleteTaskState, ProviderTransportSnapshotCacheKey,
+};
+
+#[derive(Debug, Clone)]
+pub struct AppState {
+    #[cfg(test)]
+    pub(crate) execution_runtime_override_base_url: Option<String>,
+    pub(crate) data: Arc<GatewayDataState>,
+    pub(crate) usage_runtime: Arc<usage::UsageRuntime>,
+    pub(crate) video_tasks: Arc<VideoTaskService>,
+    pub(crate) video_task_poller: Option<VideoTaskPollerConfig>,
+    pub(crate) request_gate: Option<Arc<ConcurrencyGate>>,
+    pub(crate) distributed_request_gate: Option<Arc<DistributedConcurrencyGate>>,
+    pub(crate) client: reqwest::Client,
+    pub(crate) auth_context_cache: Arc<AuthContextCache>,
+    pub(crate) auth_api_key_last_used_cache: Arc<AuthApiKeyLastUsedCache>,
+    pub(crate) oauth_refresh: Arc<provider_transport::LocalOAuthRefreshCoordinator>,
+    pub(crate) direct_plan_bypass_cache: Arc<DirectPlanBypassCache>,
+    pub(crate) scheduler_affinity_cache: Arc<SchedulerAffinityCache>,
+    pub(crate) fallback_metrics: Arc<fallback_metrics::GatewayFallbackMetrics>,
+    pub(crate) frontdoor_cors: Option<Arc<FrontdoorCorsConfig>>,
+    pub(crate) frontdoor_user_rpm: Arc<FrontdoorUserRpmLimiter>,
+    pub(crate) tunnel: crate::tunnel::EmbeddedTunnelState,
+    pub(crate) provider_transport_snapshot_cache:
+        Arc<StdMutex<HashMap<ProviderTransportSnapshotCacheKey, CachedProviderTransportSnapshot>>>,
+    pub(crate) provider_key_rpm_resets: Arc<StdMutex<HashMap<String, u64>>>,
+    pub(crate) local_execution_runtime_miss_diagnostics:
+        Arc<StdMutex<HashMap<String, LocalExecutionRuntimeMissDiagnostic>>>,
+    pub(crate) admin_monitoring_error_stats_reset_at: Arc<StdMutex<Option<u64>>>,
+    pub(crate) provider_delete_tasks:
+        Arc<StdMutex<HashMap<String, LocalProviderDeleteTaskState>>>,
+    #[cfg(test)]
+    pub(crate) provider_oauth_state_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) provider_oauth_device_session_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) provider_oauth_batch_task_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) auth_session_store: Option<
+        Arc<
+            StdMutex<HashMap<String, crate::data::state::StoredUserSessionRecord>>,
+        >,
+    >,
+    #[cfg(test)]
+    pub(crate) auth_email_verification_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) auth_email_delivery_store: Option<Arc<StdMutex<Vec<serde_json::Value>>>>,
+    #[cfg(test)]
+    pub(crate) auth_user_store: Option<
+        Arc<StdMutex<HashMap<String, aether_data::repository::users::StoredUserAuthRecord>>>,
+    >,
+    #[cfg(test)]
+    pub(crate) auth_user_model_capability_store:
+        Option<Arc<StdMutex<HashMap<String, serde_json::Value>>>>,
+    #[cfg(test)]
+    pub(crate) auth_wallet_store: Option<
+        Arc<StdMutex<HashMap<String, aether_data::repository::wallet::StoredWalletSnapshot>>>,
+    >,
+    #[cfg(test)]
+    pub(crate) admin_wallet_payment_order_store:
+        Option<Arc<StdMutex<HashMap<String, AdminWalletPaymentOrderRecord>>>>,
+    #[cfg(test)]
+    pub(crate) admin_payment_callback_store:
+        Option<Arc<StdMutex<HashMap<String, AdminPaymentCallbackRecord>>>>,
+    #[cfg(test)]
+    pub(crate) admin_wallet_transaction_store:
+        Option<Arc<StdMutex<HashMap<String, AdminWalletTransactionRecord>>>>,
+    #[cfg(test)]
+    pub(crate) admin_wallet_refund_store:
+        Option<Arc<StdMutex<HashMap<String, AdminWalletRefundRecord>>>>,
+    #[cfg(test)]
+    pub(crate) admin_billing_rule_store:
+        Option<Arc<StdMutex<HashMap<String, AdminBillingRuleRecord>>>>,
+    #[cfg(test)]
+    pub(crate) admin_billing_collector_store:
+        Option<Arc<StdMutex<HashMap<String, AdminBillingCollectorRecord>>>>,
+    #[cfg(test)]
+    pub(crate) admin_security_blacklist_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) admin_security_whitelist_store:
+        Option<Arc<StdMutex<std::collections::BTreeSet<String>>>>,
+    #[cfg(test)]
+    pub(crate) admin_monitoring_cache_affinity_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) admin_monitoring_redis_key_store:
+        Option<Arc<StdMutex<HashMap<String, String>>>>,
+    #[cfg(test)]
+    pub(crate) provider_oauth_token_url_overrides:
+        Arc<StdMutex<HashMap<String, String>>>,
+}