interactive: Host/View entry menu, clipboard copy, player picker

Bare `pixelpass` now opens a dialoguer-driven Host/View menu instead of
going straight to host mode. Host path copies the ticket to the system
clipboard via arboard with silent print-only fallback. View path
prompts for the ticket, then after the local listener binds prompts
mpv-vs-VLC and spawns it detached (setsid + null stdio) so the player
survives pixelpass exiting.

Headless invocations (`pixelpass <ticket>`, `pixelpass --repair`)
unchanged. Per spec at ~/Documents/pixelpass-interactive-mode-spec.md.

src/main.rs

@@ -1,6 +1,7 @@
 mod cli;
 mod common;
 mod host;
+mod interactive;
 mod repair;
 mod viewer;
 
@@ -24,12 +25,12 @@ async fn main() -> Result<()> {
             let ticket: EndpointTicket = s.parse().map_err(|e| {
                 anyhow::anyhow!(
                     "argument doesn't look like a pixelpass ticket ({e}).\n\
-                     Run with no arguments to host, or pass a ticket to view."
+                     Run with no arguments for the interactive menu, or pass a ticket to view."
                 )
             })?;
-            viewer::run(ticket, cli.into_viewer_opts()).await
+            viewer::run(ticket, cli.into_viewer_opts(false)).await
         }
-        None => host::run(cli.into_host_opts()).await,
+        None => interactive::run(cli).await,
     }
 }