docs: update installation guide for Deepseek AI backend

- Change base URL from OpenAI to Deepseek
- Update model name from gpt-3.5-turbo to deepseek-chat

These changes reflect the switch from OpenAI to Deepseek as the AI backend service, ensuring the documentation is accurate and up-to-date.

Author: elliotxx

docs/karpor/1-getting-started/2-installation.md

@@ -113,9 +113,9 @@ helm install karpor-release kusionstack/karpor \
 # Custom configuration
 helm install karpor-release kusionstack/karpor \
    --set server.ai.authToken={YOUR_AI_TOKEN} \
-   --set server.ai.baseUrl=https://api.openai.com/v1 \
+   --set server.ai.baseUrl=https://api.deepseek.com \
    --set server.ai.backend=openai \
-   --set server.ai.model=gpt-3.5-turbo \
+   --set server.ai.model=deepseek-chat \
    --set server.ai.topP=0.5 \
    --set server.ai.temperature=0.2
 ```

i18n/zh/docusaurus-plugin-content-docs-karpor/current/1-getting-started/2-installation.md

@@ -113,9 +113,9 @@ helm install karpor-release kusionstack/karpor \
 # 自定义配置
 helm install karpor-release kusionstack/karpor \
    --set server.ai.authToken={YOUR_AI_TOKEN} \
-   --set server.ai.baseUrl=https://api.openai.com/v1 \
+   --set server.ai.baseUrl=https://api.deepseek.com \
    --set server.ai.backend=openai \
-   --set server.ai.model=gpt-3.5-turbo \
+   --set server.ai.model=deepseek-chat \
    --set server.ai.topP=0.5 \
    --set server.ai.temperature=0.2
 ```