Simple IK Rig (no mesh - only bones) in Blender 4

Job ID: 37786669

Budget: $10 – $30 CAD

I have no experience with rigging, and need this to work.
I imagine someone who knows IK can do this is 10 minutes!

I will share Blender file if you like (must be Blender 4) from picture.
I need the middle bone (yellow) to move up and down on Z axis, and have the red bones locked in place, no movement.

Requested deliverable is the Blender file with rig working.
Extra if you can film a screen share (with voice) showing me how to set it up from beginning (proof of concept video showing IK set up and constraints).
Related categories: Blender 3D Rigging