Add error handling to translation functions

Added try-except blocks to both DeepSeek and Google translation functions to handle API errors gracefully and return an empty string on failure. Also added a check for the AI_API_KEY environment variable and improved cache update logic in translate_po_file.

translate.py

@@ -58,10 +58,15 @@ def contains_target_language_characters(text, target_lang):
         return False
 
 def translate_text_deepseek(text, target_lang):
+    api_key = os.getenv("AI_API_KEY")
+    if not api_key:
+        raise ValueError("AI_API_KEY environment variable is not set.")
+    
     client = OpenAI(
-        api_key=os.getenv("AI_API_KEY"),
+        api_key=api_key,
         base_url="https://api.deepseek.com",
     )
+    try:
         completion = client.chat.completions.create(
             model="deepseek-chat",
             messages=[
@@ -74,12 +79,19 @@ def translate_text_deepseek(text, target_lang):
         for chunk in completion:
             full_content += chunk.choices[0].delta.content
         return full_content.capitalize().lower().rstrip('.,!?;:')
+    except Exception as e:
+        print(f"DeepSeek translation failed: {e}")
+        return ""
 
 def translate_text_google(text, target_lang):
+    try:
         translator = Translator(service_urls=['translate.google.com'])
         translation = translator.translate(text, src='auto', dest=target_lang)
         translated_text = translation.text
         return translated_text.capitalize().lower().rstrip('.,!?;:')
+    except Exception as e:
+        print(f"Google Translate failed: {e}")
+        return ""
 
 def needs_fallback_translation(translated_text):
     return '\n' in translated_text or '"' in translated_text
@@ -198,6 +210,7 @@ def translate_po_file(input_file, output_file, target_lang_code, target_lang_nam
         if key not in used_translations:
             print(f"Removing unused cache entry: {key}")
             del translations[key]
+            updated = True
 
     if updated:
         save_translation_cache(cache_file, translations)