Overload now has a 10-frame hold window

This update reduces overload's ability to bank a double shot indefinitely and makes it a more timing-sensitive burst skill.

Changes:

• Overload can now be held for up to 10 frames after activation.
• If no successful shot is fired within that window, overload automatically expires.
• A successful shot inside the window still fires two bullets.
• Overload cooldown remains 32 frames.

This removes the strongest part of the old pattern: activating overload early and waiting forever for the perfect firing lane. Overload now rewards committing to a real timing read.