chore: bump dioxus-radio to 0.7 (#27)

* chore: bump dioxus-radio to 0.7

- Replace deprecated `dioxus-lib` with `dioxus` crate and explicit
sub-crates
  - Add explicit import for `ReactiveContext` (removed from prelude in
0.7)
  - Remove usage of deprecated `signal_write_in_component_body::allow`
wrapper
    - The warnings API was refactored in 0.7 and this wrapper no longer
exists
  - Add explicit lifetime annotations (`'_`) to `ReadableRef` return
types
    - Fixes Rust 2024 edition lint about mismatched lifetime syntaxes
    - Makes borrowing semantics more transparent without changing
behavior
  - Remove circular/unused warnings module re-export
  - Fix event handler return types in examples (must return `()` in 0.7)
  - Update Cargo packages

* Update Cargo.toml

* Update Cargo.toml

* Delete rust-toolchain.toml

* Delete Cargo.lock

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Co-authored-by: Marc Espin <[email protected]>

Author: brittonr