feat: 添加用户端后端 API 路由

- 新增 GET /api/user/logs（用户 API 调用历史）
- 新增 GET /api/user/summary（用户使用统计摘要）
- stats.rs: ProxyLogRow 改为 pub 供 user 模块复用

src/routes/stats.rs

@@ -156,7 +156,7 @@ async fn proxy_logs(
 }
 
 #[derive(Debug, serde::Serialize, sqlx::FromRow)]
-struct ProxyLogRow {
+pub struct ProxyLogRow {
     id: i64,
     route_id: Option<i64>,
     channel_id: Option<i64>,

src/routes/user/mod.rs

@@ -5,7 +5,7 @@ use crate::{
     AppState,
 };
 use axum::{
-    extract::{Path, State},
+    extract::{Path, State, Query},
     http::{HeaderMap, StatusCode},
     routing::{delete, get},
     Json, Router,
@@ -18,6 +18,8 @@ pub fn routes() -> Router<AppState> {
         .route("/v1/user/profile", get(get_profile).put(update_profile))
         .route("/v1/user/api-keys", get(list_api_keys).post(create_api_key))
         .route("/v1/user/api-keys/{id}", delete(delete_api_key))
+        .route("/v1/user/logs", get(get_user_logs))
+        .route("/v1/user/summary", get(get_user_summary))
 }
 
 #[derive(Debug, Deserialize)]
@@ -158,3 +160,71 @@ async fn delete_api_key(
 
     Ok(StatusCode::NO_CONTENT)
 }
+
+async fn get_user_logs(
+    State(state): State<AppState>,
+    headers: HeaderMap,
+    Query(params): Query<std::collections::HashMap<String, String>>,
+) -> AppResult<Json<Value>> {
+    let user_id = current_user_id(&headers, &state)?;
+    
+    let limit = params.get("limit").and_then(|v| v.parse::<i64>().ok()).unwrap_or(20).clamp(1, 100);
+    let offset = params.get("offset").and_then(|v| v.parse::<i64>().ok()).unwrap_or(0).max(0);
+
+    let items: Vec<Value> = sqlx::query_as::<_, crate::routes::stats::ProxyLogRow>(
+        "SELECT l.* FROM proxy_logs l
+         JOIN downstream_api_keys k ON l.downstream_api_key_id = k.id
+         WHERE k.user_id = ?
+         ORDER BY l.created_at DESC
+         LIMIT ? OFFSET ?"
+    )
+    .bind(user_id)
+    .bind(limit)
+    .bind(offset)
+    .fetch_all(&*state.db)
+    .await?
+    .into_iter()
+    .map(|row| serde_json::to_value(row).unwrap_or(json!({})))
+    .collect();
+
+    let total: i64 = sqlx::query_scalar(
+        "SELECT COUNT(*) FROM proxy_logs l
+         JOIN downstream_api_keys k ON l.downstream_api_key_id = k.id
+         WHERE k.user_id = ?"
+    )
+    .bind(user_id)
+    .fetch_one(&*state.db)
+    .await?;
+
+    Ok(Json(json!({
+        "items": items,
+        "total": total,
+        "limit": limit,
+        "offset": offset
+    })))
+}
+
+async fn get_user_summary(
+    State(state): State<AppState>,
+    headers: HeaderMap,
+) -> AppResult<Json<Value>> {
+    let user_id = current_user_id(&headers, &state)?;
+
+    let stats: (i64, i64, f64) = sqlx::query_as(
+        "SELECT COUNT(*), 
+                SUM(CASE WHEN l.status = 'success' THEN 1 ELSE 0 END),
+                COALESCE(SUM(l.estimated_cost), 0.0)
+         FROM proxy_logs l
+         JOIN downstream_api_keys k ON l.downstream_api_key_id = k.id
+         WHERE k.user_id = ?"
+    )
+    .bind(user_id)
+    .fetch_one(&*state.db)
+    .await?;
+
+    Ok(Json(json!({
+        "totalRequests": stats.0,
+        "successRequests": stats.1,
+        "totalCost": stats.2,
+    })))
+}