docs: update README, Stdlib, BuildAndTest, PLAN for new std modules
Added documentation for:
- Std::Fs (DirExists, Mkdir, ListDir)
- Std::Mem (Alloc, Free, MemEq, New)
- Std::Set<T> (Set_New, Set_Add, Set_Has)
- String_Find, String_Replace, String_Format
Updated PLAN.md blockers (all resolved) and self-host status.
Updated README.md project structure and feature table.
Updated BuildAndTest.md with new stdlib modules and path syntax.
Also includes:
- CLI path argument fix (build/check/run accept project path)
- Remove dummyFunc from parser
- Fix String_Replace to use String_Concat instead of buggy str_join2
dimgigov
291de88506