test_camera was the only Catch2 target missing the `if(TARGET glm::glm)`
link block — every other test linked glm but this one didn't, so the
macOS arm64 builder failed to find `glm/glm.hpp` from camera.hpp.
Five fopen call sites in tools/editor/cli_* passed
fs::directory_entry::path().c_str() — that's wchar_t* on Windows.
Routed them through `.string().c_str()` so MSYS2 GCC and clang both
accept the const char* parameter.
Continues the modularization. Moves --gen-zone-readme and
--gen-project-readme into their own translation unit using the
established handle<Family> dispatch pattern. Consolidated the
trailing --out flag parser into a single parseOutFlag helper
(was duplicated between the two handlers).
main.cpp drops 27,736 → 27,445 lines (-291). Behavior unchanged
(verified by re-generating README and PROJECT.md, contents
identical to pre-refactor output).
