Eliminate quote/proc-macro2 deps from dioxus-config-macro crate

[nicoburns]

Summary

dioxus-config-macro only ever emits { #input } or (), each of which is a single proc_macro::Group, so quote!/proc_macro2 are unnecessary. The macros now build the output directly with the proc_macro API:

fn group(delimiter: Delimiter, stream: TokenStream) -> TokenStream {
    TokenTree::Group(Group::new(delimiter, stream)).into()
}
// cfg on:  group(Delimiter::Brace, input)
// cfg off: group(Delimiter::Parenthesis, TokenStream::new())

Output is token-for-token identical: Group::new spans with Span::call_site(), which is what quote! used too.

Verified with cargo clippy -p dioxus-config-macro --all-features -- -D warnings and cargo check -p dioxus --features web,server.

Link to Devin session: https://dioxus.staging.devinenterprise.com/sessions/25f5c2bd8df547a596e96b65e2b92029
Open in Devin Desktop: https://dioxus.staging.devinenterprise.com/desktop/session/25f5c2bd8df547a596e96b65e2b92029?variant=devin-insiders
Requested by: @nicoburns

[staging-devin-ai-integration]

I'll fix CI failures and address comments from users with write access that start with 'Devin'.

• Disable automatic comment, CI, and merge conflict monitoring