When building for wasm32v1-none with Cargo, the 'std' feature gets
unified across the dependency graph, meaning serde_core sees
feature="std" even on a no_std target. This caused compilation failures
because the crate tried to use std:: imports.
This commit fixes the issue by checking target_os = "none" in addition
to the std feature flag:
- lib.rs: Force no_std when target_os = "none"
- crate_root.rs: Use core/alloc instead of std on target_os = "none"
- All std-only cfg blocks now include not(target_os = "none")
- Add explicit prelude imports for wasm32v1-none compatibility
pezkuwichain
David Tolnay