Enforce a consistent include ordering convention across the codebase: wren_common.h (as configuration header) first, followed by the module's own header, then other wren_*.h headers in lexicographic order, and finally standard library includes. Also add missing wren_common.h include to main.c and wren_io.c, and add _CRT_SECURE_NO_WARNINGS define for MSVC in wren_common.h.