feat(gui): auto-copy the host ticket on start, with a copied indicator

The CLI/interactive host auto-copies the ticket to the clipboard and says so;
the GUI host only offered a manual Copy button. Users conditioned by the CLI
assumed the GUI auto-copied too, didn't click Copy, and pasted whatever stale
ticket was already in the clipboard — then dialed a dead host and saw an
unexplained "can't connect". (Compounded by flaky Wayland clipboard / KDE
Connect sync.)

Now the ticket is copied the moment it arrives (same arboard path as the
manual button), with a green "✓ Copied to clipboard" confirmation. Auto-copy
failure is non-fatal: the code stays visible, is now selectable for manual
copy, and a hint tells the user to click Copy. Verified: clicking only Start
lands a fresh ticket in the clipboard (wl-paste).

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

src/gui/mod.rs

@@ -34,6 +34,15 @@ pub fn run() -> anyhow::Result<()> {
     .map_err(|e| anyhow::anyhow!("GUI failed to start: {e}"))
 }
 
+/// Best-effort clipboard write. Returns whether it succeeded so callers can
+/// show an honest "✓ Copied" / fallback hint (the clipboard can be flaky on
+/// Wayland, and a silent miss is what left users pasting stale tickets).
+fn set_clipboard(text: &str) -> bool {
+    arboard::Clipboard::new()
+        .and_then(|mut cb| cb.set_text(text.to_owned()))
+        .is_ok()
+}
+
 /// Which screen the single window is currently showing.
 #[derive(Default, PartialEq)]
 enum Screen {
@@ -117,6 +126,11 @@ struct HostState {
     active: u32,
     max: u32,
     capturing: bool,
+    /// Whether the current ticket made it onto the clipboard (auto-copy on
+    /// arrival, or a manual Copy click). Drives the "✓ Copied" hint so the
+    /// user isn't left guessing whether to click Copy — the trap that had
+    /// people pasting a stale clipboard ticket.
+    copied: bool,
     last_refusal: Option<String>,
     error: Option<String>,
 }
@@ -134,6 +148,7 @@ impl Default for HostState {
             active: 0,
             max: 0,
             capturing: false,
+            copied: false,
             last_refusal: None,
             error: None,
         }
@@ -329,11 +344,29 @@ impl PixelPassApp {
             ui.label("Share this code with your viewer(s):");
             ui.add_space(4.0);
             egui::Frame::group(ui.style()).show(ui, |ui| {
-                ui.add(egui::Label::new(egui::RichText::new(&ticket).monospace().small()).wrap());
+                ui.add(
+                    egui::Label::new(egui::RichText::new(&ticket).monospace().small())
+                        .wrap()
+                        .selectable(true),
+                );
             });
             ui.add_space(4.0);
-            if ui.button("📋 Copy code").clicked() {
-                self.copy_to_clipboard(&ticket);
+            ui.horizontal(|ui| {
+                if ui.button("📋 Copy code").clicked() {
+                    self.copy_to_clipboard(&ticket);
+                }
+                if self.host.copied {
+                    ui.colored_label(egui::Color32::LIGHT_GREEN, "✓ Copied to clipboard");
+                }
+            });
+            if !self.host.copied {
+                ui.label(
+                    egui::RichText::new(
+                        "Couldn't auto-copy — click Copy, or select the code above.",
+                    )
+                    .small()
+                    .weak(),
+                );
             }
         }
 
@@ -362,6 +395,7 @@ impl PixelPassApp {
         self.host.active = 0;
         self.host.max = 0;
         self.host.capturing = false;
+        self.host.copied = false;
 
         let mut args = vec![
             "--host".to_string(),
@@ -392,6 +426,7 @@ impl PixelPassApp {
         self.host.proc = None;
         self.host.capturing = false;
         self.host.ticket = None;
+        self.host.copied = false;
     }
 
     /// Drain the host child's event channel into state, and detect an
@@ -424,7 +459,15 @@ impl PixelPassApp {
 
     fn apply_host_event(&mut self, ev: ChildEvent) {
         match ev {
-            ChildEvent::Ticket { value } => self.host.ticket = Some(value),
+            ChildEvent::Ticket { value } => {
+                // Auto-copy on arrival, mirroring the CLI/interactive host
+                // (which copies the ticket and prints "copied to your
+                // clipboard"). A failure here is non-fatal: the ticket stays
+                // visible for manual copy, and `copied` stays false so the UI
+                // doesn't falsely claim success.
+                self.host.copied = set_clipboard(&value);
+                self.host.ticket = Some(value);
+            }
             ChildEvent::HostInfo {
                 display_server,
                 capture,
@@ -456,9 +499,18 @@ impl PixelPassApp {
         }
     }
 
+    /// Manual Copy-button handler: copy and reflect success in the UI, or
+    /// surface a clear error if the clipboard rejected it.
     fn copy_to_clipboard(&mut self, text: &str) {
-        if let Err(e) = arboard::Clipboard::new().and_then(|mut cb| cb.set_text(text.to_owned())) {
-            self.host.error = Some(format!("Clipboard copy failed: {e}"));
+        if set_clipboard(text) {
+            self.host.copied = true;
+            self.host.error = None;
+        } else {
+            self.host.copied = false;
+            self.host.error = Some(
+                "Couldn't write to the clipboard. Select the code above and copy it manually."
+                    .to_string(),
+            );
         }
     }