feat: 包含 Kotlin 原始代码和 Rust Windows 桌面版

- flomo-ai/: Android Kotlin 原始项目
- flomo-ai-desktop/: Rust + egui Windows 桌面移植版
  - LLM API 调用、提示词管理、主题切换、配置持久化
  - MinGW 工具链编译，无控制台窗口

flomo-ai-desktop/src/api/llm_client.rs

@@ -0,0 +1,93 @@
+use crate::config::AppSettings;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ChatMessage {
+    pub role: String,
+    pub content: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ChatCompletionRequest {
+    pub model: String,
+    pub messages: Vec<ChatMessage>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ChatChoice {
+    pub message: ChatMessage,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ChatCompletionResponse {
+    pub choices: Vec<ChatChoice>,
+}
+
+pub fn call_llm(settings: &AppSettings, user_input: String, selected_prompt: Option<String>) -> Result<String, String> {
+    let mut messages = Vec::new();
+
+    if let Some(prompt) = selected_prompt {
+        if !prompt.is_empty() {
+            messages.push(ChatMessage {
+                role: "system".to_string(),
+                content: prompt,
+            });
+        }
+    }
+
+    messages.push(ChatMessage {
+        role: "user".to_string(),
+        content: user_input,
+    });
+
+    let request = ChatCompletionRequest {
+        model: settings.llm_config.model.clone(),
+        messages,
+    };
+
+    let client = reqwest::blocking::Client::builder()
+        .timeout(std::time::Duration::from_secs(120))
+        .build()
+        .map_err(|e| format!("Failed to create HTTP client: {}", e))?;
+
+    let mut req_builder = client
+        .post(format!("{}/chat/completions", settings.llm_config.base_url))
+        .header("Content-Type", "application/json");
+
+    if !settings.llm_config.api_key.is_empty() {
+        req_builder = req_builder.header("Authorization", format!("Bearer {}", settings.llm_config.api_key));
+    }
+
+    for header in &settings.header_configs {
+        if !header.key.is_empty() {
+            req_builder = req_builder.header(&header.key, &header.value);
+        }
+    }
+
+    let body = serde_json::to_string(&request)
+        .map_err(|e| format!("Failed to serialize request: {}", e))?;
+
+    let response = req_builder
+        .body(body)
+        .send()
+        .map_err(|e| format!("Request failed: {}", e))?;
+
+    if !response.status().is_success() {
+        let status = response.status();
+        let error_body = response.text().unwrap_or_default();
+        return Err(format!("API error {}: {}", status, error_body));
+    }
+
+    let response_text = response
+        .text()
+        .map_err(|e| format!("Failed to read response: {}", e))?;
+
+    let completion: ChatCompletionResponse = serde_json::from_str(&response_text)
+        .map_err(|e| format!("Failed to parse response: {}", e))?;
+
+    if completion.choices.is_empty() {
+        return Err("No response from API".to_string());
+    }
+
+    Ok(completion.choices[0].message.content.clone())
+}