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/usage/reporting/context.rs

@@ -1,20 +1,14 @@
 use aether_data::repository::video_tasks::VideoTaskLookupKey;
-use serde_json::{Map, Value};
+use aether_usage_runtime::{
+    build_locally_actionable_report_context_from_request_candidate,
+    build_locally_actionable_report_context_from_video_task,
+};
+use serde_json::Value;
 
-use crate::gateway::AppState;
+use crate::video_tasks::{resolve_video_task_report_lookup, VideoTaskReportLookup};
+use crate::AppState;
 
-pub(crate) fn report_context_is_locally_actionable(report_context: Option<&Value>) -> bool {
-    let Some(context) = report_context else {
-        return false;
-    };
-
-    has_non_empty_str(context, "request_id")
-        && (has_non_empty_str(context, "candidate_id")
-            || has_u64(context, "candidate_index")
-            || has_non_empty_str(context, "provider_id")
-            || has_non_empty_str(context, "endpoint_id")
-            || has_non_empty_str(context, "key_id"))
-}
+pub(crate) use aether_usage_runtime::report_context_is_locally_actionable;
 
 pub(crate) async fn resolve_locally_actionable_report_context(
     state: &AppState,
@@ -61,143 +55,38 @@ async fn resolve_locally_actionable_report_context_from_request_candidates(
         return None;
     }
 
-    let mut object = context.as_object()?.clone();
-    let candidate = &existing_candidates[0];
-    insert_missing_string_value(&mut object, "candidate_id", Some(&candidate.id));
-    if !object.contains_key("candidate_index") {
-        object.insert(
-            "candidate_index".to_string(),
-            Value::Number(candidate.candidate_index.into()),
-        );
-    }
-    insert_missing_optional_string_value(
-        &mut object,
-        "provider_id",
-        candidate.provider_id.as_deref(),
-    );
-    insert_missing_optional_string_value(
-        &mut object,
-        "endpoint_id",
-        candidate.endpoint_id.as_deref(),
-    );
-    insert_missing_optional_string_value(&mut object, "key_id", candidate.key_id.as_deref());
-    insert_missing_optional_string_value(&mut object, "user_id", candidate.user_id.as_deref());
-    insert_missing_optional_string_value(
-        &mut object,
-        "api_key_id",
-        candidate.api_key_id.as_deref(),
-    );
-
-    let resolved = Value::Object(object);
-    report_context_is_locally_actionable(Some(&resolved)).then_some(resolved)
+    build_locally_actionable_report_context_from_request_candidate(context, &existing_candidates[0])
 }
 
 async fn resolve_locally_actionable_report_context_from_video_task(
     state: &AppState,
     context: &Value,
 ) -> Option<Value> {
-    let local_task_id = context
-        .get("local_task_id")
-        .and_then(Value::as_str)
-        .map(str::trim)
-        .filter(|value| !value.is_empty());
-    let local_short_id = context
-        .get("local_short_id")
-        .and_then(Value::as_str)
-        .map(str::trim)
-        .filter(|value| !value.is_empty());
-    let task_id = context
-        .get("task_id")
-        .and_then(Value::as_str)
-        .map(str::trim)
-        .filter(|value| !value.is_empty());
-    let user_id = context
-        .get("user_id")
-        .and_then(Value::as_str)
-        .map(str::trim)
-        .filter(|value| !value.is_empty());
-
-    let task = if let Some(task_id) = local_task_id {
-        state
-            .data
-            .find_video_task(VideoTaskLookupKey::Id(task_id))
-            .await
-            .ok()??
-    } else if let Some(short_id) = local_short_id {
-        state
-            .data
-            .find_video_task(VideoTaskLookupKey::ShortId(short_id))
-            .await
-            .ok()??
-    } else if let Some(task_id) = task_id {
-        if let Some(task) = state
-            .data
-            .find_video_task(VideoTaskLookupKey::Id(task_id))
-            .await
-            .ok()?
-        {
-            task
-        } else {
-            let user_id = user_id?;
-            state
-                .data
-                .find_video_task(VideoTaskLookupKey::UserExternal {
-                    user_id,
-                    external_task_id: task_id,
-                })
-                .await
-                .ok()??
+    let task = match resolve_video_task_report_lookup(context)? {
+        VideoTaskReportLookup::Lookup(lookup) => {
+            state.data.find_video_task(lookup).await.ok()??
+        }
+        VideoTaskReportLookup::TaskIdOrExternal { task_id, user_id } => {
+            if let Some(task) = state
+                .data
+                .find_video_task(VideoTaskLookupKey::Id(task_id))
+                .await
+                .ok()?
+            {
+                task
+            } else {
+                let user_id = user_id?;
+                state
+                    .data
+                    .find_video_task(VideoTaskLookupKey::UserExternal {
+                        user_id,
+                        external_task_id: task_id,
+                    })
+                    .await
+                    .ok()??
+            }
         }
-    } else {
-        return None;
     };
 
-    let mut object = context.as_object()?.clone();
-    insert_missing_string_value(&mut object, "request_id", Some(task.request_id.as_str()));
-    insert_missing_optional_string_value(&mut object, "provider_id", task.provider_id.as_deref());
-    insert_missing_optional_string_value(&mut object, "endpoint_id", task.endpoint_id.as_deref());
-    insert_missing_optional_string_value(&mut object, "key_id", task.key_id.as_deref());
-    insert_missing_optional_string_value(&mut object, "user_id", task.user_id.as_deref());
-    insert_missing_optional_string_value(&mut object, "api_key_id", task.api_key_id.as_deref());
-    insert_missing_optional_string_value(
-        &mut object,
-        "client_api_format",
-        task.client_api_format.as_deref(),
-    );
-    insert_missing_optional_string_value(
-        &mut object,
-        "provider_api_format",
-        task.provider_api_format.as_deref(),
-    );
-    Some(Value::Object(object))
-}
-
-fn insert_missing_string_value(object: &mut Map<String, Value>, key: &str, value: Option<&str>) {
-    if object.contains_key(key) {
-        return;
-    }
-    let Some(value) = value.map(str::trim).filter(|value| !value.is_empty()) else {
-        return;
-    };
-    object.insert(key.to_string(), Value::String(value.to_string()));
-}
-
-fn insert_missing_optional_string_value(
-    object: &mut Map<String, Value>,
-    key: &str,
-    value: Option<&str>,
-) {
-    insert_missing_string_value(object, key, value);
-}
-
-fn has_non_empty_str(value: &Value, key: &str) -> bool {
-    value
-        .get(key)
-        .and_then(Value::as_str)
-        .map(str::trim)
-        .is_some_and(|value| !value.is_empty())
-}
-
-fn has_u64(value: &Value, key: &str) -> bool {
-    value.get(key).and_then(Value::as_u64).is_some()
+    build_locally_actionable_report_context_from_video_task(context, &task)
 }