Maximize header space and enable tab scrolling

Remove application title from main header bar and wrap tabs in scrollable container. This prevents window resizing when many tabs are open and follows modern GNOME app patterns.

src/main-window.ui

@@ -4,7 +4,6 @@
   <requires lib="Adw" version="1.0"/>
 
   <template class="RosterWindow" parent="AdwApplicationWindow">
-    <property name="title">Roster</property>
     <property name="default-width">1200</property>
     <property name="default-height">800</property>
     <property name="content">
@@ -96,12 +95,20 @@
             <!-- Main Header Bar -->
             <child>
               <object class="AdwHeaderBar">
-                <!-- Tab bar container on the left (hidden when only 1 tab) -->
+                <property name="show-title">False</property>
+                <!-- Tab bar in scrollable container (hidden when only 1 tab) -->
                 <child type="start">
+                  <object class="GtkScrolledWindow" id="tab_bar_scroll">
+                    <property name="hscrollbar-policy">automatic</property>
+                    <property name="vscrollbar-policy">never</property>
+                    <property name="propagate-natural-width">true</property>
+                    <property name="visible">False</property>
+                    <child>
                       <object class="GtkBox" id="tab_bar_container">
                         <property name="orientation">horizontal</property>
                         <property name="spacing">0</property>
-                    <property name="visible">False</property>
+                      </object>
+                    </child>
                   </object>
                 </child>
 

src/window.py

@@ -44,6 +44,7 @@ class RosterWindow(Adw.ApplicationWindow):
     url_entry = Gtk.Template.Child()
     send_button = Gtk.Template.Child()
     new_request_button = Gtk.Template.Child()
+    tab_bar_scroll = Gtk.Template.Child()
     tab_bar_container = Gtk.Template.Child()
 
     # Panes
@@ -426,7 +427,7 @@ class RosterWindow(Adw.ApplicationWindow):
         """Show/hide tab bar based on number of tabs."""
         num_tabs = len(self.tab_manager.tabs)
         # Show tab bar only if we have 2 or more tabs
-        self.tab_bar_container.set_visible(num_tabs >= 2)
+        self.tab_bar_scroll.set_visible(num_tabs >= 2)
 
         # Update tab bar with buttons
         if num_tabs >= 2: