refactor(examples/basic): use typed error handling with format_transport_error

- Use format_transport_error() helper for user-friendly error messages
- Replace generic error handling with typed Eip1193Error methods
- Add user_message() calls for chain switch errors
- Improve error logging with error codes

Author: mfw78

examples/basic/Cargo.toml

@@ -8,9 +8,15 @@ leptos.workspace = true
 leptos_meta.workspace = true
 leptos_router.workspace = true
 leptos-rainbowkit = { path = "../../crates/leptos-rainbowkit" }
+alloy.workspace = true
+alloy-eip1193 = { path = "../../crates/alloy-eip1193" }
 console_log.workspace = true
 log.workspace = true
 console_error_panic_hook.workspace = true
+hex = "0.4"
+serde = { version = "1.0", features = ["derive"] }
+serde_json.workspace = true
+gloo-timers = { version = "0.3", features = ["futures"] }
 
 [profile.release]
 opt-level = 'z'