feat: switch AI to Gemini and improve translation workflow

src/services/gemini.ts

@@ -0,0 +1,32 @@
+export async function generateGemini(prompt: string, systemPrompt: string): Promise<string> {
+  const apiKey = import.meta.env.GEMINI_API_KEY || localStorage.getItem('GEMINI_API_KEY') || '';
+  if (!apiKey) {
+    throw new Error('Gemini API Key not found. Please set GEMINI_API_KEY in .env or GEMINI_API_KEY in localStorage.');
+  }
+
+  const response = await fetch(`https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash-exp:generateContent?key=${apiKey}`, {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json'
+    },
+    body: JSON.stringify({
+      contents: [{
+        parts: [{
+          text: `${systemPrompt}\n\nTask: ${prompt}`
+        }]
+      }],
+      generationConfig: {
+        maxOutputTokens: 1000,
+        temperature: 0.7
+      }
+    })
+  });
+
+  if (!response.ok) {
+    const errorData = await response.json().catch(() => ({}));
+    throw new Error(errorData.error?.message || 'Failed to generate text from Gemini API');
+  }
+
+  const data = await response.json();
+  return data.candidates[0].content.parts[0].text;
+}