2026-08-31 - Implemented Syscall 477 (mmap) and wired to the syscall table (D412)

Implemented mmap (Syscall 477, FreeBSD SYS_mmap, MAP_PRIVATE | MAP_ANON) in orbistoun-kernel and orbistoun-posix, backed by mappings().reserve(). Added knowledge entries in libkernel.toml and libScePosix.toml, and verified that symbols::syscalls() automatically binds Syscall 477 to mmap.