feat: add deepseek provider scaffolding

tests/deepseek_provider_test.rs

@@ -0,0 +1,67 @@
+use std::sync::{Mutex, OnceLock};
+
+use serde_json::json;
+use sgclaw::config::DeepSeekSettings;
+use sgclaw::llm::{ChatMessage, DeepSeekProvider, ToolDefinition};
+
+fn env_lock() -> &'static Mutex<()> {
+    static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+    LOCK.get_or_init(|| Mutex::new(()))
+}
+
+#[test]
+fn deepseek_settings_load_defaults_from_env() {
+    let _guard = env_lock().lock().unwrap();
+    std::env::set_var("DEEPSEEK_API_KEY", "test-key");
+    std::env::remove_var("DEEPSEEK_BASE_URL");
+    std::env::remove_var("DEEPSEEK_MODEL");
+
+    let settings = DeepSeekSettings::from_env().unwrap();
+
+    assert_eq!(settings.api_key, "test-key");
+    assert_eq!(settings.base_url, "https://api.deepseek.com");
+    assert_eq!(settings.model, "deepseek-chat");
+}
+
+#[test]
+fn deepseek_request_shape_matches_openai_compatible_chat_format() {
+    let provider = DeepSeekProvider::new(DeepSeekSettings {
+        api_key: "test-key".to_string(),
+        base_url: "https://api.deepseek.com".to_string(),
+        model: "deepseek-chat".to_string(),
+    });
+    let messages = vec![
+        ChatMessage {
+            role: "system".to_string(),
+            content: "You are sgClaw.".to_string(),
+        },
+        ChatMessage {
+            role: "user".to_string(),
+            content: "打开百度搜索天气".to_string(),
+        },
+    ];
+    let tools = vec![ToolDefinition {
+        name: "browser_action".to_string(),
+        description: "Execute browser actions".to_string(),
+        parameters: json!({
+            "type": "object",
+            "properties": {
+                "action": { "type": "string" }
+            },
+            "required": ["action"]
+        }),
+    }];
+
+    let request = provider.build_chat_request(&messages, &tools);
+    let serialized = serde_json::to_value(&request).unwrap();
+
+    assert_eq!(serialized["model"], "deepseek-chat");
+    assert_eq!(serialized["stream"], false);
+    assert_eq!(serialized["messages"][0]["role"], "system");
+    assert_eq!(serialized["messages"][1]["content"], "打开百度搜索天气");
+    assert_eq!(serialized["tools"][0]["type"], "function");
+    assert_eq!(
+        serialized["tools"][0]["function"]["name"],
+        "browser_action"
+    );
+}