chore: clear clippy warnings and refresh the GUI README

`cargo clippy --fix`: drop needless borrows in interactive.rs, remove an
unneeded `return`, and derive `Default` for `HostState` / the config struct
instead of hand-writing it. No behaviour change.

README: the GUI host screen now lists connected viewers with a Kick button
and notifies on join/leave — update the description, which still mentioned
only a "live viewer count".

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/interactive.rs

@@ -13,7 +13,7 @@ pub async fn run(cli: Cli) -> Result<()> {
     let theme = ColorfulTheme::default();
     let choice = Select::with_theme(&theme)
         .with_prompt("What do you want to do?")
-        .items(&[
+        .items([
             "Host (share my screen)",
             "View (watch someone else's screen)",
         ])
@@ -112,7 +112,7 @@ fn pick_quality(theme: &ColorfulTheme) -> Result<Quality> {
 
     let choice = Select::with_theme(theme)
         .with_prompt("What quality should the viewer(s) get?")
-        .items(&items)
+        .items(items)
         .default(0)
         .interact()?;
 
@@ -138,7 +138,7 @@ pub async fn run_reconfigure() -> Result<()> {
 async fn preflight_if_needed(theme: &ColorfulTheme) {
     let mut cfg = config::load().unwrap_or_default();
     match cfg.bandwidth.status {
-        config::BandwidthStatus::Measured | config::BandwidthStatus::Skipped => return,
+        config::BandwidthStatus::Measured | config::BandwidthStatus::Skipped => (),
         config::BandwidthStatus::Unmeasured => {
             eprintln!();
             eprintln!("First-time setup");
@@ -154,7 +154,7 @@ async fn preflight_if_needed(theme: &ColorfulTheme) {
 
             let Ok(choice) = Select::with_theme(theme)
                 .with_prompt("What would you like to do?")
-                .items(&[
+                .items([
                     "Run the bandwidth test (recommended)",
                     "Skip — use the conservative default",
                 ])
@@ -180,7 +180,7 @@ async fn preflight_if_needed(theme: &ColorfulTheme) {
             eprintln!();
             let Ok(choice) = Select::with_theme(theme)
                 .with_prompt("Last bandwidth test failed. Try again?")
-                .items(&[
+                .items([
                     "Yes — retry now",
                     "No — use the conservative default",
                 ])
@@ -341,7 +341,7 @@ pub fn prompt_player() -> Result<Player> {
     let theme = ColorfulTheme::default();
     let choice = Select::with_theme(&theme)
         .with_prompt("Connected. Pick a player to launch")
-        .items(&["mpv", "VLC"])
+        .items(["mpv", "VLC"])
         .default(0)
         .interact()?;
     Ok(if choice == 0 { Player::Mpv } else { Player::Vlc })