Coverage crunch: libc, elf, hle

159 tests added across six new integration files, all under tests/ so nothing collided with work in flight elsewhere in the tree.

file	before	after
orbistoun-libc/src/cstring.rs	0.96%	99.04%
orbistoun-libc/src/lib.rs	57.95%	90.50%
orbistoun-libc/src/math.rs	0.00%	73.13%
orbistoun-elf/src/lib.rs	49.19%	73.56%
orbistoun-libc overall	59.17%	90.06%

Reaching the private functions through the public implementations() table turned out to be the right shape rather than a workaround: a test there exercises exactly what a resolved import exercises, so a function dropped from the table fails these even while it compiles - the same bug as a module registered without its implementations (D281).

One real bug

strtod and strtof advanced the end pointer past skipped whitespace even when nothing converted. C says the pointer stays at the original string when no conversion is performed, and cstring.rs's integer parser already did exactly that - so the two families disagreed with each other. Two lines, in math.rs.

Two surprises worth keeping

A failing test binary writes no coverage profile at all. Written up properly in docs/TESTING.md; the short version is that orbistoun-hle was reported at 23% while actually at 95%, because one unrelated unit test was failing. Every zero in a coverage report is two different facts wearing one number.

Two of the tests were wrong where the code was right, and both were worth the detour: a dynamic segment outside every PT_LOAD is still located through its own header, and strtok writes one terminator per token rather than replacing every delimiter. The tests now assert the real contract and say why.

One suspicion measured and dropped

vendor_name_table and needed_libraries resolve info.strtab with vaddr_to_offset while raw_imports uses table_offset, which reads like D247 surviving at two sites. It is not: attribution on a real commercial module produces libSceAgc, libSceHttp2, libSceAvPlayer - names orbistoun does not declare, so they came from the module's own table. Checked before reporting, which is the lesson from the pad-name episode.

Deliberately not tested

abort and exit reach orbistoun_core::stop, which is diverging and calls std::process::exit - calling either would take the test binary down and report every other test in the file as never having run. Named in the file's header so the absence reads as a decision.