feat(paste): auto-insert transcript at cursor via wtype/xdotool/ydotool/osascript/SendKeys

Adds an opt-in "auto-paste into focused window" toggle. When enabled, the
dictation pipeline sets the clipboard and then sends a Ctrl+V / Cmd+V
keystroke to whatever window currently has focus — the common case after a
global-hotkey dictation, since Kon's own window never stole focus.

Backend (src-tauri/src/commands/paste.rs) probes for a platform paste tool
and falls back cleanly:
- Linux Wayland: wtype > ydotool > xdotool
- Linux X11: xdotool > ydotool > wtype
- macOS: osascript System Events keystroke
- Windows: PowerShell WScript.Shell SendKeys

detect_paste_backends is a pure probe used by Settings to describe the
available backend next to the toggle (or nudge the user to install one).
paste_text always copies first, so auto-paste failure degrades to the
existing clipboard-only behaviour and surfaces a warn toast.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/pages/SettingsPage.svelte

@@ -22,6 +22,13 @@
   let engineOk = $state(false);
   let downloadedModels = $state([]);
   let runtimeCapabilities = $state(null);
+  let pasteBackends = $state([]);
+  let pasteBackendsDescription = $derived.by(() => {
+    if (pasteBackends.length === 0) {
+      return "Install wtype (Wayland) or xdotool (X11) to enable auto-paste. Focus must already be on the target window.";
+    }
+    return `Uses ${pasteBackends.join(", ")}. Focus must already be on the target window.`;
+  });
   let downloadingModel = $state("");
   let downloadProgress = $state(0);
   let unlisten = null;
@@ -541,6 +548,12 @@
       downloadedModels = await invoke("list_models");
     } catch {}
 
+    try {
+      pasteBackends = (await invoke("detect_paste_backends")) || [];
+    } catch {
+      pasteBackends = [];
+    }
+
     // Parakeet status
     try {
       parakeetOk = await invoke("check_parakeet_engine");
@@ -1498,6 +1511,11 @@
           <div class="px-5 pb-5 animate-fade-in">
             <div class="space-y-0.5">
               <Toggle bind:checked={settings.autoCopy} label="Auto-copy to clipboard" />
+              <Toggle
+                bind:checked={settings.autoPaste}
+                label="Auto-paste into focused window"
+                description={pasteBackendsDescription}
+              />
               <Toggle bind:checked={settings.includeTimestamps} label="Include timestamps in exports" />
               <Toggle
                 bind:checked={settings.saveAudio}