Why the MTU Calculator I Wished Existed: Stackable Tunnel Overhead, Per-Vendor MSS Clamp Commands, and Shareable Links

Most online MTU calculators stop at 'GRE adds 24 bytes.' Real networks stack encapsulations — VXLAN over IPsec, GRE over IPsec, MPLS-then-VXLAN — and need the actual adjust-mss command for the device you're configuring. So I built one that does both.