Update src/app.py

lets users enter an OpenAI api key if they have one

src/app.py

@@ -112,6 +112,18 @@ with st.sidebar:
         key="model_selector_radio" # Unique Key Added for Safety
     )
     st.info(f"Connected to: **{model_choice}**")
+
+    # --- REGULAR USER OPENAI API KEY ---
+    user_api_key = st.text_input(
+        "OpenAI API Key (Optional)", 
+        type="password", 
+        help="Enter your own key to bypass limits."
+    )
+    
+    if user_api_key:
+        st.session_state.user_openai_key = user_api_key
+    else:
+        st.session_state.user_openai_key = None
     
     st.divider()
     st.header("⚙️ Controls")
@@ -177,10 +189,18 @@ def query_local_model(messages, max_tokens, model_name):
         return f"Connection Error: {e}", None
 
 def query_openai_model(messages, max_tokens):
-    if not OPENAI_KEY:
-        return "Error: OPENAI_API_KEY not set.", None
+    # 1. Check for User Key first
+    api_key_to_use = st.session_state.get("user_openai_key")
+    
+    # 2. Fallback to System Key
+    if not api_key_to_use:
+        api_key_to_use = OPENAI_KEY
+
+    # 3. Final Safety Check
+    if not api_key_to_use:
+        return "Error: No API Key available. Please enter one in the sidebar.", None
     
-    client = OpenAI(api_key=OPENAI_KEY)
+    client = OpenAI(api_key=api_key_to_use)
     
     try:
         response = client.chat.completions.create(