fix: dedupe repeated inline rows in list output

[immanuwell]

list <obj> <prog> can print the same row twice when an inline helper gets reused at different call sites. In plain text those rows look identical, so its just noise.

Repro on main

1. go run ./cmd/stackwhere list ./testdata/basic.o cil_entry
2. At R10-32: you get two_inlined_a twice and two_inlined_b twice

Fix

• dedupe display-identical rows in plain text output
• keep JSON and --call-stack untouched, so the full call-site detail still shows up there

Checks

• go test ./...

[immanuwell]

@dylandreimerink WDYT?

[dylandreimerink]

Nice, thank you!