fix(build): exempt build scripts and proc-macros from release strip

`wasm-pack build --release` died with "can't find crate" for rustversion,
then thiserror_impl, then every other proc-macro. Cargo strips debuginfo
from release artifacts by default and on macOS that takes the metadata
proc-macro dylibs need to be loadable with it, so rustc could no longer
open them.

Debug builds are unstripped, which is why the whole test suite stayed
green while the browser REPL could not be built for production at all.

Stripping buys nothing for build scripts and proc-macros, so
[profile.release.build-override] exempts them; release binaries stay
stripped.

Also pins wafer-core to 0.2.3 in wafer-web and wafer-cli — both still
asked for 0.2.1. The caret requirement resolved, so nothing broke.

crates/web/Cargo.toml

@@ -12,7 +12,7 @@ workspace = true
 crate-type = ["cdylib", "rlib"]
 
 [dependencies]
-wafer-core = { path = "../core", version = "0.2.1", default-features = false, features = ["crypto"] }
+wafer-core = { path = "../core", version = "0.2.3", default-features = false, features = ["crypto"] }
 wasm-bindgen = "0.2"
 js-sys = "0.3"
 send_wrapper = { workspace = true }