refactor: rename app.py to main.py for clarity

The filename was changed to better reflect its role as the main entry point of the application. This makes the project structure more intuitive for new developers.

Author: chiqors

Dockerfile

@@ -11,7 +11,7 @@ COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
 # Copy application code
-COPY app.py .
+COPY main.py .
 
 # Set environment variables
 ENV PORT=8080