…g-level-from-args"

This reverts commit 4ce5f06.

This commit reverts a previous modification to the flag handling logic
in the agent and server's main() functions.

A prior change introduced a condition (`if local.Lookup("v") == nil`)
before setting the default klog verbosity level. This condition was
incorrect because `klog.InitFlags()` always defines the `-v` flag,
meaning the default verbosity was never being applied. This caused the
effective log level to fall back to klog's default of `0` instead of the
intended `4`.

This change restores the original, correct behavior by unconditionally
setting the verbosity to `4`. This ensures logs are visible by default
while still allowing the user to override the setting via the command
line.