Switch SSR examples from wasm-logger to tracing-web

[Copilot]

The two SSR examples (simple_ssr, ssr_router) used wasm-logger/log for browser-side logging. These are migrated to tracing-web + tracing-subscriber, consistent with the pattern established in yew-trunk-minimal-template.

Changes

• Cargo.toml (workspace): Add tracing-web = "0.1" and tracing-subscriber = { version = "0.3", features = ["fmt"] } as workspace dependencies.
• examples/simple_ssr/Cargo.toml / examples/ssr_router/Cargo.toml: Replace wasm-logger (and log) with tracing-web + tracing-subscriber in [target.'cfg(target_arch = "wasm32")'.dependencies].
• *_hydrate.rs binaries: Replace wasm_logger::init(...) with a tracing-subscriber registry backed by MakeWebConsoleWriter.

#[cfg(target_arch = "wasm32")]
{
    let fmt_layer = tracing_subscriber::fmt::layer()
        .with_ansi(false) // Only partially supported across browsers
        .without_time()   // std::time is not available in browsers
        .with_writer(tracing_web::MakeWebConsoleWriter::new());
    use tracing_subscriber::prelude::*;
    tracing_subscriber::registry().with(fmt_layer).init();
}

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