daemon: replace atoi() with strtoul_ui() and strtol_i()

daemon: replace atoi() with strtoul_ui() and strtol_i()

Replace atoi() with strtoul_ui() for --timeout and --init-timeout
(non-negative integers) and with strtol_i() for --max-connections
(signed integers). This improves error handling and input validation
by detecting invalid values and providing clear error messages.
Update tests to ensure these arguments are properly validated.

Signed-off-by: Usman Akinyemi <redacted>
Signed-off-by: Taylor Blau <redacted>