feat(ui): themed startup splash with deferred window show (#1030)

* feat(ui): add themed startup splash with deferred window show

Show a theme-aware loading splash before the Vite bundle mounts, hide the
native window until it paints, and use per-theme logo gradient colors.

* docs: note startup splash in CHANGELOG and credits for PR #1030

* docs: attribute PR #1030 startup splash to cucadmuh

src-tauri/src/lib.rs

@@ -97,6 +97,10 @@ pub fn run() {
         .plugin(tauri_plugin_updater::Builder::new().build())
         .plugin(
             tauri_plugin_window_state::Builder::default()
+                .with_state_flags(
+                    tauri_plugin_window_state::StateFlags::all()
+                        & !tauri_plugin_window_state::StateFlags::VISIBLE,
+                )
                 .with_denylist(&["mini"])
                 .build()
         )
@@ -625,6 +629,24 @@ pub fn run() {
                 }
             }
         })
+        .on_page_load(|webview, payload| {
+            if webview.label() != "main" {
+                return;
+            }
+
+            match payload.event() {
+                tauri::webview::PageLoadEvent::Started => {
+                    let window = webview.window().clone();
+                    std::thread::spawn(move || {
+                        std::thread::sleep(std::time::Duration::from_millis(48));
+                        let _ = window.show();
+                    });
+                }
+                tauri::webview::PageLoadEvent::Finished => {
+                    let _ = webview.window().show();
+                }
+            }
+        })
         .invoke_handler(tauri::generate_handler![
             greet,
             theme_import::import_theme_zip,

src-tauri/tauri.conf.json

@@ -22,7 +22,8 @@
         "fullscreen": false,
         "decorations": true,
         "transparent": false,
-        "visible": true,
+        "visible": false,
+        "backgroundColor": "#1e1e2e",
         "dragDropEnabled": false
       }
     ],