Friction-and-wishlist from one real profiling/verification session, not a
defect report. Highlights: demangling and trace({over,capture}) worked well;
pc-range checks are treacherous when helpers sit adjacent to the function
under test (symbol extent, not address, is the missing primitive); no
float/vector register access forced the XMM verification out to objdump.
Wishlist, JS-expressible first: symStart/symSize (or inFn), countTo, hexdump
— candidates for a v0.9 prelude with no Rust changes. xmm reads and
prologue-aware breakpoints need native support.
