fix: 三端联调测试 2 P0 + 6 P1 + 2 P2 修复

P0-1: SaaS relay 模型别名解析 — "glm-4-flash" → "glm-4-flash-250414" (resolve_model)
P0-2: config.rs interpolate_env_vars UTF-8 修复 (chars 迭代器替代 bytes as char)
      + DB 启动编码检查 + docker-compose UTF-8 编码参数

P1-3: UI 模型选择器覆盖 Agent 默认模型 (model_override 全链路: TS→Tauri→Rust kernel)
P1-6: 知识搜索管道修复 — seed_knowledge 创建 chunks + 默认分类 (seed/uploaded/distillation)
P1-7: 用量限额从当前 Plan 读取 (非 stale usage 表)
P1-8: relay 双维度配额检查 (relay_requests + input_tokens)

P2-9: SSE 路径 token 计数修复 — 流结束检测替代固定 500ms sleep + billing increment

crates/zclaw-saas/src/relay/handlers.rs

@@ -152,8 +152,8 @@ pub async fn chat_completions(
         }
         ModelResolution::Group(candidates)
     } else {
-        // 向后兼容：直接模型查找
-        let target_model = state.cache.get_model(model_name)
+        // 向后兼容：直接模型查找 + 别名解析（如 "glm-4-flash" → "glm-4-flash-250414"）
+        let target_model = state.cache.resolve_model(model_name)
             .ok_or_else(|| SaasError::NotFound(format!("模型 {} 不存在或未启用", model_name)))?;
 
         // 获取 provider 信息 — 使用内存缓存消除 DB 查询
@@ -218,7 +218,7 @@ pub async fn chat_completions(
         ModelResolution::Direct(ref candidate) => {
             // 单 Provider 直接路由（向后兼容）
             match service::execute_relay(
-                &state.db, &task.id, &candidate.provider_id,
+                &state.db, &task.id, &ctx.account_id, &candidate.provider_id,
                 &candidate.base_url, &request_body, stream,
                 max_attempts, retry_delay_ms, &enc_key,
                 true, // 独立调用，管理 task 状态
@@ -233,7 +233,7 @@ pub async fn chat_completions(
             // SSE 一旦开始流式传输，中途上游断连不会触发 failover（SSE 协议固有限制）。
             service::sort_candidates_by_quota(&state.db, candidates).await;
             service::execute_relay_with_failover(
-                &state.db, &task.id, candidates,
+                &state.db, &task.id, &ctx.account_id, candidates,
                 &request_body, stream,
                 max_attempts, retry_delay_ms, &enc_key
             ).await
@@ -553,11 +553,12 @@ pub async fn retry_task(
     // 异步执行重试 — 根据解析结果选择执行路径
     let db = state.db.clone();
     let task_id = id.clone();
+    let account_id_for_spawn = task.account_id.clone();
     let handle = tokio::spawn(async move {
         let result = match model_resolution {
             ModelResolution::Direct(ref candidate) => {
                 service::execute_relay(
-                    &db, &task_id, &candidate.provider_id,
+                    &db, &task_id, &account_id_for_spawn, &candidate.provider_id,
                     &candidate.base_url, &body, stream,
                     max_attempts, base_delay_ms, &enc_key,
                     true,
@@ -566,7 +567,7 @@ pub async fn retry_task(
             ModelResolution::Group(ref mut candidates) => {
                 service::sort_candidates_by_quota(&db, candidates).await;
                 service::execute_relay_with_failover(
-                    &db, &task_id, candidates,
+                    &db, &task_id, &account_id_for_spawn, candidates,
                     &body, stream,
                     max_attempts, base_delay_ms, &enc_key,
                 ).await