fix(providers): verify qwen against official docs

- checkModel: qwen-turbo → qwen-flash（官方说 qwen-turbo 不再更新）
- qwen-turbo.maxOutput: 16384 → 8192（官方上限）
- qwen-max.contextWindowTokens: 131072 → 32768（官方当前 ctx 是 32K）

来源：https://help.aliyun.com/zh/model-studio/getting-started/models
R2-5。

packages/core/src/llm/providers/endpoints/qwen.ts

@@ -5,7 +5,7 @@ export const QWEN: InkosEndpoint = {
   label: "通义千问",
   api: "openai-completions",
   baseUrl: "https://dashscope.aliyuncs.com/compatible-mode/v1",
-  checkModel: "qwen-turbo",
+  checkModel: "qwen-flash",
   temperatureRange: [0, 2],
   defaultTemperature: 0.7,
   writingTemperature: 1,
@@ -51,12 +51,12 @@ export const QWEN: InkosEndpoint = {
     { id: "qwq-plus", displayName: "QwQ Plus", maxOutput: 8192, contextWindowTokens: 131072, abilities: { reasoning: true, functionCall: true, search: true }, releasedAt: "2025-03-05" },
     { id: "qwen3.5-flash", displayName: "Qwen3.5 Flash", maxOutput: 65536, contextWindowTokens: 1000000, abilities: { reasoning: true, vision: true, functionCall: true, search: true }, enabled: true, releasedAt: "2026-02-24" },
     { id: "qwen-flash", displayName: "Qwen Flash", maxOutput: 32768, contextWindowTokens: 1000000, abilities: { reasoning: true, functionCall: true, search: true }, releasedAt: "2025-07-28" },
-    { id: "qwen-turbo", displayName: "Qwen Turbo", maxOutput: 16384, contextWindowTokens: 1000000, abilities: { reasoning: true, functionCall: true, search: true }, releasedAt: "2025-07-15" },
+    { id: "qwen-turbo", displayName: "Qwen Turbo", maxOutput: 8192, contextWindowTokens: 1000000, abilities: { reasoning: true, functionCall: true, search: true }, releasedAt: "2025-07-15" },
     { id: "qwen3.5-plus", displayName: "Qwen3.5 Plus", maxOutput: 65536, contextWindowTokens: 1000000, abilities: { reasoning: true, vision: true, functionCall: true, search: true }, enabled: true, releasedAt: "2026-02-15" },
     { id: "qwen-plus", displayName: "Qwen Plus", maxOutput: 32768, contextWindowTokens: 1000000, abilities: { reasoning: true, functionCall: true, search: true } },
     { id: "qwen3-max", displayName: "Qwen3 Max", maxOutput: 65536, contextWindowTokens: 262144, abilities: { reasoning: true, functionCall: true, search: true }, enabled: true, releasedAt: "2026-01-23" },
     { id: "qwen3-max-preview", displayName: "Qwen3 Max Preview", maxOutput: 65536, contextWindowTokens: 262144, abilities: { reasoning: true, functionCall: true, search: true }, releasedAt: "2025-10-30" },
-    { id: "qwen-max", displayName: "Qwen Max", maxOutput: 8192, contextWindowTokens: 131072, abilities: { functionCall: true, search: true } },
+    { id: "qwen-max", displayName: "Qwen Max", maxOutput: 8192, contextWindowTokens: 32768, abilities: { functionCall: true, search: true } },
     { id: "qwen-long", displayName: "Qwen Long", maxOutput: 32768, contextWindowTokens: 10000000, abilities: { functionCall: true } },
     { id: "qwen3.5-omni-plus", displayName: "Qwen3.5 Omni Plus", maxOutput: 65536, contextWindowTokens: 262144, abilities: { vision: true, search: true }, releasedAt: "2026-03-30" },
     { id: "qwen3.5-omni-flash", displayName: "Qwen3.5 Omni Flash", maxOutput: 65536, contextWindowTokens: 262144, abilities: { vision: true, search: true }, releasedAt: "2026-03-30" },