fix: validate empty input in Word-Building game to prevent IndexError

Closes steam-bell-92#1312

Add .strip() and empty-string check before accessing user_word[0].
Empty input was crashing with 'IndexError: string index out of range'
on lines 41 and 56.

Author: vipul674

games/Word-Building/word_building.py

@@ -37,7 +37,10 @@ def Main():
     # Game loop
     while True:
         # User input and validation
-        user_word = input("Your word: ")
+        user_word = input("Your word: ").strip()
+        if not user_word:
+            print("\nPlease enter a valid word!")
+            continue
         if (bot_word is not None) and (user_word[0].lower() != bot_word[-1].lower()):
             print("\nInvalid word! Your word must start with the last letter of bot's word.")
             win = False