Make C/S/X exploitation prompt case-insensitive

[Copilot]

The interactive exploitation prompt rejected lowercase input (c, s, x), forcing users to re-enter their answer in uppercase.

Changes

• coercer/core/tasks/execute.py: Replaced the while … not in loop (which required pre-initialized state) with a cleaner while True / break pattern that strips, uppercases, and validates the first character in one pass — accepting both cases transparently.

# Before
next_action_answer = None
while next_action_answer not in ["C", "S", "X"]:
    next_action_answer = input("Continue (C) | Skip this function (S) | Stop exploitation (X) ? ")
    if len(next_action_answer) > 0:
        next_action_answer = next_action_answer.strip()[0].upper()

# After
while True:
    next_action_answer = input("Continue (C) | Skip this function (S) | Stop exploitation (X) ? ")
    if next_action_answer:
        first = next_action_answer.strip()[0].upper()
        if first in ["C", "S", "X"]:
            next_action_answer = first
            break

Empty input (bare Enter) continues to re-prompt. Any trailing characters after the first valid key are silently ignored.