feat: add transcription backend contracts

src-tauri/src/transcription/openai.rs

@@ -0,0 +1,19 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct OpenAiTranscriptionConfig {
+    pub endpoint: String,
+    pub model: String,
+    pub language: Option<String>,
+}
+
+impl Default for OpenAiTranscriptionConfig {
+    fn default() -> Self {
+        Self {
+            endpoint: "https://api.openai.com/v1/audio/transcriptions".to_string(),
+            model: "whisper-1".to_string(),
+            language: None,
+        }
+    }
+}