Fixes #1569

Describe the changes you have made in this PR -

app/cli/support/prompt_support.py: In _patched_ask(), added except (OSError, KeyError, RuntimeError) to catch asyncio/selector failures when prompt_toolkit registers stdin (fd 0) in the event loop. Prints a clear message and calls sys.exit(1) so the process exits cleanly instead of crashing with a cryptic traceback

Demo/Screenshot for feature changes and bug fixes -

Before (crash):

$ opensre onboard
? How do you want to get started?
KeyError: '0 is not registered'
  File "asyncio/selector_events.py", line 282, in _add_reader
    key = self._selector.get_key(fd)
  File "selectors.py", line 192, in get_key
    raise KeyError("{!r} is not registered".format(fileobj)) from None

OSError: [Errno 22] Invalid argument

After (clean exit):

$ opensre onboard
? How do you want to get started?

The interactive prompt could not be displayed due to a terminal I/O error on this platform.

Code Understanding and AI Usage

Did you use AI assistance (ChatGPT, Claude, Copilot, etc.) to write any part of this code?

• No, I wrote all the code myself
• Yes, I used AI assistance (continue below)

If you used AI assistance:

• I have reviewed every single line of the AI-generated code
• I can explain the purpose and logic of each function/component I added
• I have tested edge cases and understand how the code handles them
• I have modified the AI output to follow this project's coding standards and conventions

Explain your implementation approach:

• What problem does your code solve? When prompt_toolkit's asyncio event loop tries to register stdin (fd 0) via epoll_ctl or select, the syscall can fail on some platforms, raising OSError or KeyError. These propagate unhandled because _patched_ask only catches KeyboardInterrupt, and main() only catches SystemExit/ClickException — so the user sees a full crash traceback.
• What alternative approaches did you consider? I considered setting an asyncio event loop policy (e.g. SelectSelector fallback) but that's fragile and platform-specific. I also considered adding a general except Exception to main(), but that would suppress legitimate bugs elsewhere. The targeted catch at the failure site is the most minimal and safe.
• Why did you choose this specific implementation? The _patched_ask closure is the exact point where the asyncio failure occurs. Catching (OSError, KeyError, RuntimeError) there and calling sys.exit(1) gives the user a clear message. SystemExit(1) propagates untouched through Exception handlers (it inherits from BaseException) and is cleanly caught by main()'s existing except SystemExit handler.
• What are the key functions/components and what do they do? _patched_ask() is a closure that wraps questionary's unsafe_ask() in a retry loop for Ctrl+C double-exit handling. It's installed globally by install_questionary_ctrl_c_double_exit() onto every questionary prompt type (select, text, confirm, etc.). The new catch block covers the selector failure path without interfering with the existing Ctrl+C and Escape handling.

Checklist before requesting a review

• I have added proper PR title and linked to the issue
• I have performed a self-review of my code
• I can explain the purpose of every function, class, and logic block I added
• I understand why my changes work and have tested them thoroughly
• I have considered potential edge cases and how my code handles them
• If it is a core feature, I have added thorough tests
• My code follows the project's style guidelines and conventions

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