Enhance tab grouping logic to correctly handle pinned tabs and improv…

…e insertion behavior

src/browser/components/tabbrowser/content/tabbrowser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tabbrowser.js b/browser/components/tabbrowser/content/tabbrowser.js
-index 628aa6596627c85efe361fc1ece8fd58f7ee653e..fe746cd0e749308889173cbbb32b8a77a1dfe10f 100644
+index 628aa6596627c85efe361fc1ece8fd58f7ee653e..dc1bf702844ab60eb781c12dd59d29e839577cdb 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -412,11 +412,50 @@
@@ -194,19 +194,16 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..fe746cd0e749308889173cbbb32b8a77
        // Additionally send pinned tab events
        if (pinned) {
          this._notifyPinnedStatus(t);
-@@ -2918,9 +2982,10 @@
+@@ -2918,7 +2982,8 @@
          id = `${Date.now()}-${Math.round(Math.random() * 100)}`;
        }
        let group = this._createTabGroup(id, color, false, label);
 -      this.tabContainer.insertBefore(
 +      group.pinned = tabs.some(tab => tab.pinned);
 +      (group.pinned ? this.verticalPinnedTabsContainer : this.tabContainer).insertBefore(
          group,
--        insertBefore?.group ?? insertBefore
-+        insertBefore?.group ?? tabs[tabs.length - 1].nextElementSibling
+         insertBefore?.group ?? insertBefore
        );
-       group.addTabs(tabs);
-
 @@ -3367,6 +3432,24 @@
          ) {
            tabWasReused = true;