feat(sidebar): wire configurable expanded width through a single source

HellionChat/Ui/Components/Settings/Tabs/ChannelsTab.cs

@@ -60,16 +60,14 @@ internal sealed class ChannelsTab
                 () => Plugin.Config.SidebarTabView,
                 v => Plugin.Config.SidebarTabView = v
             );
-            // Range covers the on-disk default (44) plus Master-Spec §4.1 reference
-            // (38px icon-only, 150px expanded). An earlier 120-400 range would clamp
-            // the default 44 up to 120 silently. 30 leaves headroom for a future
-            // ultra-tight icon-only mode; 300 stays above the 150 expanded reference
-            // without giving the slider an absurd ceiling.
+            // Range matches Sidebar.MinSidebarWidth/MaxSidebarWidth (40-300). The
+            // lower bound sits just above the 38px icon-only threshold; the
+            // on-disk default (44) and the 150px expanded reference both fit.
             DrawSliderInt(
                 "Sidebar width",
                 () => Plugin.Config.SidebarWidth,
                 v => Plugin.Config.SidebarWidth = v,
-                30,
+                40,
                 300
             );
         }

HellionChat/Ui/Components/Sidebar.cs

@@ -11,7 +11,7 @@ using Microsoft.Extensions.Logging;
 namespace HellionChat.Ui.Components;
 
 // Channel-list panel pinned to the left of the chat window. Auto-switches
-// between an icon-only column (38px) and an expanded column (150px) once
+// between an icon-only column (38px) and an expanded column (Config.SidebarWidth) once
 // the outer window crosses Config.SidebarAutoSwitchThresholdPx. The
 // pop-out affordance (hover button + right-click menu) routes through the
 // injected ChannelPopoutPool via TryOpen, which reserves a slot and binds
@@ -19,7 +19,12 @@ namespace HellionChat.Ui.Components;
 internal sealed class Sidebar
 {
     public const float IconOnlyWidth = 38f;
-    public const float ExpandedWidth = 150f;
+
+    // B1-3a: expanded sidebar width is user-configurable (Config.SidebarWidth),
+    // clamped to these bounds (matches the ChannelsTab slider range). Replaces
+    // the old fixed 150px ExpandedWidth constant.
+    public const float MinSidebarWidth = 40f;
+    public const float MaxSidebarWidth = 300f;
 
     private const float RowHeight = 32f;
     private const float PopOutHitWidth = 22f;
@@ -72,7 +77,9 @@ internal sealed class Sidebar
         windowWidth >= Plugin.Config.SidebarAutoSwitchThresholdPx;
 
     public float GetWidth(float windowWidth) =>
-        IsExpanded(windowWidth) ? ExpandedWidth : IconOnlyWidth;
+        IsExpanded(windowWidth)
+            ? Math.Clamp((float)Plugin.Config.SidebarWidth, MinSidebarWidth, MaxSidebarWidth)
+            : IconOnlyWidth;
 
     public void Draw(float windowWidth, IList<Tab> tabs, ref Tab? activeTab)
     {
@@ -83,7 +90,7 @@ internal sealed class Sidebar
         }
 
         var expanded = IsExpanded(windowWidth);
-        var width = expanded ? ExpandedWidth : IconOnlyWidth;
+        var width = GetWidth(windowWidth);
         using var child = ImRaii.Child("##hellion-sidebar", new Vector2(width, 0));
         if (!child.Success)
             return;