Enhance first-boot script and documentation for eMMC provisioning: add structured logging, improve package installation process, and implement one-shot autostart for rotation and wallpaper setup. Update dashboard to manage portal file descriptions and enhance admin interface with new navigation links.

chromium-setup/emmc-provisioning/cloud-init/files-from-guard/plymouth-custom/custom.plymouth

@@ -0,0 +1,8 @@
+[Plymouth Theme]
+Name=Custom Splash
+Description=Custom boot splash screen
+ModuleName=script
+
+[script]
+ImageDir=/usr/share/plymouth/themes/custom
+ScriptFile=/usr/share/plymouth/themes/custom/custom.script

chromium-setup/emmc-provisioning/cloud-init/files-from-guard/plymouth-custom/custom.script

@@ -0,0 +1,40 @@
+screen_width = Window.GetWidth();
+screen_height = Window.GetHeight();
+
+theme_image = Image("splash.png");
+image_width = theme_image.GetWidth();
+image_height = theme_image.GetHeight();
+
+scale_x = image_width / screen_width;
+scale_y = image_height / screen_height;
+
+if (scale_x > 1 || scale_y > 1)
+{
+    if (scale_x > scale_y)
+    {
+        resized_image = theme_image.Scale(screen_width, image_height / scale_x);
+        image_x = 0;
+        image_y = (screen_height - ((image_height * screen_width) / image_width)) / 2;
+    }
+    else
+    {
+        resized_image = theme_image.Scale(image_width / scale_y, screen_height);
+        image_x = (screen_width - ((image_width * screen_height) / image_height)) / 2;
+        image_y = 0;
+    }
+}
+else
+{
+    resized_image = theme_image.Scale(image_width, image_height);
+    image_x = (screen_width - image_width) / 2;
+    image_y = (screen_height - image_height) / 2;
+}
+
+if (Plymouth.GetMode() != "shutdown")
+{
+    sprite = Sprite(resized_image);
+    sprite.SetPosition(image_x, image_y, -100);
+}
+
+fun message_callback(text) {
+}