fix(tabs): pin indicator, history preload, drop Promote from temp menu

Smoke-test round 2 feedback from Jin:
- Promote-to-permanent label "Dauerhaft behalten" was indistinguishable
  from Pin in German, leading to misclicks that dropped the tell-target.
  Removed the menu entry from TempTabs entirely — Promote stays as a
  service method for future use, but the user-facing path is gone. Anyone
  who wants a regular tab can still create one via the existing
  "neuen Tab anlegen" flow.
- No visual confirmation that pin took effect. Added a FontAwesome
  thumbtack overlay top-left of the sidebar icon, accent-coloured, and
  appended a "Pinned — survives relog" line to the hover tooltip.
- Pinned tabs came back empty after a full disable/enable cycle because
  Tab.Messages is NonSerialized. RehydratePinnedTabs now also runs the
  same MessageStore-backed PreloadHistory the spawn path uses, so the
  recent conversation window reappears alongside the rehydrated
  TellTarget.

Diagnose-logging on TryPin/Unpin/Promote/Rehydrate stays in so the next
smoke can confirm at a glance which path fired from the Dalamud console.

HellionChat/Ui/ChatLogWindow.cs

@@ -1871,11 +1871,34 @@ public sealed class ChatLogWindow : Window
                             );
                     }
 
+                    // Pin indicator: small thumbtack glyph top-left of the icon.
+                    // Sits opposite the unread dot so they never collide.
+                    if (tab.IsPinned)
+                    {
+                        var min = ImGui.GetItemRectMin();
+                        const float pinPadding = 2f;
+                        var pinPos = new Vector2(min.X + pinPadding, min.Y + pinPadding);
+                        using (Plugin.FontManager.FontAwesome.Push())
+                        {
+                            ImGui
+                                .GetWindowDrawList()
+                                .AddText(
+                                    pinPos,
+                                    ColourUtil.RgbaToAbgr(theme.Colors.Accent),
+                                    FontAwesomeIcon.Thumbtack.ToIconString()
+                                );
+                        }
+                    }
+
                     // Tooltip mit Tab-Name + Unread-Counter beim Hover.
                     if (ImGui.IsItemHovered())
                     {
                         using var tt = ImRaii.Tooltip();
                         ImGui.TextUnformatted($"{tab.Name}{unread}");
+                        if (tab.IsPinned)
+                        {
+                            ImGui.TextUnformatted(HellionStrings.PinTab_PinnedTooltip);
+                        }
                     }
 
                     DrawTabContextMenu(tab, tabI);
@@ -2182,22 +2205,18 @@ public sealed class ChatLogWindow : Window
                 if (svc.TryPin(tab))
                     ImGui.CloseCurrentPopup();
             }
-            if (atCap && ImGui.IsItemHovered(ImGuiHoveredFlags.AllowWhenDisabled))
+            if (ImGui.IsItemHovered(ImGuiHoveredFlags.AllowWhenDisabled))
+            {
                 ImGui.SetTooltip(
-                    string.Format(
-                        HellionStrings.PinTab_LimitReached,
-                        AutoTellTabsService.MaxPinnedTempTabs
-                    )
+                    atCap
+                        ? string.Format(
+                            HellionStrings.PinTab_LimitReached,
+                            AutoTellTabsService.MaxPinnedTempTabs
+                        )
+                        : HellionStrings.PinTab_PinTooltip
                 );
+            }
         }
-
-        if (ImGui.MenuItem(HellionStrings.PinTab_MenuPromote))
-        {
-            svc.PromoteToPermanent(tab);
-            ImGui.CloseCurrentPopup();
-        }
-        if (ImGui.IsItemHovered())
-            ImGui.SetTooltip(HellionStrings.PinTab_PromoteTooltip);
     }
 
     internal readonly List<bool> PopOutDocked = [];