perf: reduce startup work and fix grade analytics bar chart animation

Batch settings storage writes, tier plugin startup, lazy-load heavy UI
chunks, and optimize global search indexing. Stop tweening bar height in
grade analytics to prevent invalid negative SVG rect values.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/seqta/utils/settingsPopup.ts

@@ -0,0 +1,33 @@
+type SettingsPopupCallback = () => void;
+
+/**
+ * Singleton that notifies listeners when the in-page settings popup closes.
+ * Used by the colour picker and other overlays tied to ExtensionPopup.
+ */
+class SettingsPopup {
+  private static instance: SettingsPopup;
+  private listeners: Set<SettingsPopupCallback> = new Set();
+
+  private constructor() {}
+
+  public static getInstance(): SettingsPopup {
+    if (!SettingsPopup.instance) {
+      SettingsPopup.instance = new SettingsPopup();
+    }
+    return SettingsPopup.instance;
+  }
+
+  public addListener(callback: SettingsPopupCallback): void {
+    this.listeners.add(callback);
+  }
+
+  public removeListener(callback: SettingsPopupCallback): void {
+    this.listeners.delete(callback);
+  }
+
+  public triggerClose(): void {
+    this.listeners.forEach((callback) => callback());
+  }
+}
+
+export const settingsPopup = SettingsPopup.getInstance();