Nion 0.7.5

修复

• 自定义 Provider 冷启动后 baseUrl 丢失，导致流式请求异常 Expected URL scheme http or https but no scheme was found for /chat/...
• 提取 resolveProvider 统一 Provider 配置解析逻辑，修复 applyProviderConfig、switchToConfig、ReminderLlmClient 三处相同问题

Fixes

• Custom provider baseUrl lost after cold start, causing streaming request error Expected URL scheme http or https but no scheme was found for /chat/...
• Extracted resolveProvider to unify provider config resolution, fixed the same issue in applyProviderConfig, switchToConfig, and ReminderLlmClient