refactor: 重构目录结构，后端代码统一到 backend/ 目录

backend/configs/agent/only-one-agent.yaml

@@ -0,0 +1,23 @@
+ai:
+  agent:
+    config:
+      tables:
+        myAgent:
+          app-name: myAgent
+          agent:
+            agent-id: "10001"
+            agent-name: "my-assistant"
+            agent-desc: "通用 AI 助手"
+          module:
+            ai-api:
+              base-url: ${OPENAI_BASE_URL}
+              api-key: ${OPENAI_API_KEY}
+            chat-model:
+              model: "gpt-4"
+            agents:
+              - name: "assistant"
+                description: "通用助手"
+                instruction: |
+                  你是一个有帮助的 AI 助手。请用中文回答用户的问题。
+            runner:
+              agent-name: "assistant"

backend/configs/application.yaml

@@ -0,0 +1,13 @@
+app:
+  name: goloom
+  env: local
+
+server:
+  addr: ":8091"
+
+llm:
+  request-timeout: 5m
+
+agent:
+  config-paths:
+    - configs/agent/only-one-agent.yaml