Show app version from Tauri instead of sidecar

The version label was reading from backendStore.version which comes
from the sidecar's version.py (hardcoded at build time). Now uses
Tauri's getVersion() API which reads from tauri.conf.json -- the
actual app version that gets bumped by the release workflow.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/App.svelte

@@ -15,6 +15,7 @@
   let sidecarState = $state<SidecarState>("checking");
   let debugLog = $state("");
   let availableUpdate = $state("");
+  let appVersion = $state("");
 
   let obsDisplayUrl = $derived(backendStore.obsUrl);
   let syncDisplayUrl = $derived(backendStore.syncUrl);
@@ -108,6 +109,14 @@
   }
 
   onMount(() => {
+    // Get app version from Tauri
+    import("@tauri-apps/api/app").then(({ getVersion }) =>
+      getVersion().then((v) => { appVersion = v; })
+    ).catch(() => {
+      // Browser dev mode -- read from package.json or use fallback
+      appVersion = "dev";
+    });
+
     checkAndLaunchSidecar();
 
     return () => {
@@ -201,7 +210,7 @@
     <TranscriptionDisplay />
     <Controls />
 
-    <div class="version-label">v{backendStore.version}</div>
+    <div class="version-label">v{appVersion || backendStore.version}</div>
   </div>
 
   {#if showSettings}