feat: 新增 LLM checker 支持大模型服务应用层拨测

基于 AI SDK v6 实现 openai/openai-responses/anthropic 三类 provider 的 http/stream 模式调用
支持 output/finishReason/usage/stream 等完整 expect 断言链路
新增 9 个源文件和 5 个测试文件共 78 个测试
更新 README/DEVELOPMENT/probes.example.yaml 和 probe-config.schema.json

probes.example.yaml

@@ -228,3 +228,41 @@ targets:
       payload: "<14>health check"
     expect:
       responded: false
+
+  - id: "llm-openai-probe"
+    name: "OpenAI Chat Completions 健康检查"
+    type: llm
+    group: "AI 服务"
+    llm:
+      provider: openai
+      url: "https://api.openai.com/v1"
+      model: "gpt-4o-mini"
+      prompt: "Say OK"
+      key: "${OPENAI_API_KEY}"
+    expect:
+      status:
+        - 200
+      finishReason: "stop"
+      output:
+        - contains: "OK"
+
+  - id: "llm-anthropic-stream-probe"
+    name: "Anthropic 流式健康检查"
+    type: llm
+    group: "AI 服务"
+    llm:
+      provider: anthropic
+      url: "https://api.anthropic.com/v1"
+      model: "claude-3-5-haiku-20241022"
+      prompt: "Say OK"
+      key: "${ANTHROPIC_API_KEY}"
+      mode: stream
+    expect:
+      status:
+        - 200
+      stream:
+        completed: true
+        firstTokenMs:
+          lte: 5000
+      finishReason: "stop"
+      maxDurationMs: 15000