Refactor app.py: Replace os.environ with os.getenv for API key retrieval

app.py

@@ -6,8 +6,8 @@ from firecrawl import FirecrawlApp
 from groq import Groq
 
 # Initialize API clients
-firecrawl_client = FirecrawlApp(api_key=os.environ["FIRECRAWL_API_KEY"])
-groq_client = Groq(api_key=os.environ["GROQ_API_KEY"])
+firecrawl_client = FirecrawlApp(api_key=os.getenv("FIRECRAWL_API_KEY"))
+groq_client = Groq(api_key=os.getenv("GROQ_API_KEY"))
 
 
 def search_flights(origin: str, destination: str, limit: int = 5):