chore(app): scaffold tauri 2 + react + vite, window launches

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src-tauri/capabilities/default.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "../node_modules/@tauri-apps/cli/schema/capability.json",
+  "identifier": "default",
+  "description": "Default capability for spacesh app",
+  "windows": ["main"],
+  "permissions": [
+    "core:default",
+    "core:event:default",
+    "core:window:default",
+    "core:app:default",
+    "core:resources:default",
+    "core:menu:default",
+    "core:tray:default"
+  ]
+}