added UI end-to-end tests for example prompts and output panel

[Rachel602144]

tests: add UI end-to-end tests for example prompts and output panel

• Added automated UI tests for key PromptView interactions:
  • Clear button resets input to placeholder
  • Surprise Me button inserts a random idea
  • Example prompt buttons insert the correct prompt text
  • Generate button updates the output panel with generated HTML
• Ensured tests run headless with dummy callbacks
• Verified tests pass successfully on local environment

Closes #19

[PrakharDoneria]

When I try running the command pytest
I got the following module not found error

PS D:\Projects\Karbon Desktop> python -u "d:\Projects\Karbon Desktop\ui.py"
invalid command name "1781760714496typewriter_effect"
    while executing
"1781760714496typewriter_effect"
    ("after" script)
invalid command name "1781761260480cycle_colors"
    while executing
"1781761260480cycle_colors"
    ("after" script)
invalid command name "1781761232000update_ai_status_indicator"
    while executing
"1781761232000update_ai_status_indicator"
    ("after" script)
invalid command name "1781761260608animate_welcome"
    while executing
"1781761260608animate_welcome"
    ("after" script)

 *  History restored 

PS D:\Projects\Karbon Desktop> 
 *  History restored 

PS D:\Projects\Karbon Desktop> pytest
================================================================ test session starts =================================================================
platform win32 -- Python 3.13.2, pytest-8.4.1, pluggy-1.6.0
rootdir: D:\Projects\Karbon Desktop
plugins: anyio-4.9.0
collected 5 items / 1 error                                                                                                                           

======================================================================= ERRORS =======================================================================
______________________________________________________ ERROR collecting test_pyautogui_basic.py ______________________________________________________
ImportError while importing test module 'D:\Projects\Karbon Desktop\test_pyautogui_basic.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
D:\Python\Lib\importlib\__init__.py:88: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
test_pyautogui_basic.py:1: in <module>
    import pyautogui
E   ModuleNotFoundError: No module named 'pyautogui'
============================================================== short test summary info =============================================================== 
ERROR test_pyautogui_basic.py
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 
================================================================== 1 error in 4.53s ================================================================== 
PS D:\Projects\Karbon Desktop>