feat(main): ribbon opens the panel as a tab, tab and sidedock leaves reused separately

src/main.ts

@@ -163,7 +163,7 @@ export default class BeaverPlugin extends Plugin {
     this.addSettingTab(new BeaverSettingsTab(this.app, this));
     this.registerView(VIEW_TYPE_PANEL, (leaf) => new PanelView(leaf, this));
     this.addRibbonIcon("bot", "Beaver", () => {
-      this.openPanel("side").catch(() => undefined);
+      this.openPanel("tab").catch(() => undefined);
     });
 
     this.addCommand({
@@ -279,10 +279,16 @@ export default class BeaverPlugin extends Plugin {
   }
 
   // Reveal a panel (creating one on first use) and, given an id, show it.
+  // A tab and a sidedock column can coexist; each placement reuses its own.
   async openPanel(placement: "side" | "tab", id?: string): Promise<void> {
     const { workspace } = this.app;
+    const inTabs = (candidate: WorkspaceLeaf) =>
+      candidate.getRoot() === workspace.rootSplit;
     let leaf: WorkspaceLeaf | null =
-      workspace.getLeavesOfType(VIEW_TYPE_PANEL)[0] ?? null;
+      workspace
+        .getLeavesOfType(VIEW_TYPE_PANEL)
+        .find((candidate) => inTabs(candidate) === (placement === "tab")) ??
+      null;
     if (!leaf) {
       leaf =
         placement === "tab"