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/AutoTellTabsService.cs

@@ -64,18 +64,38 @@ internal sealed class AutoTellTabsService : IDisposable
         _initialized = true;
     }
 
-    private static void RehydratePinnedTabs()
+    private void RehydratePinnedTabs()
     {
+        var pinned = Plugin.Config.Tabs.Count(TabLifecycleHelpers.IsInPinnedPool);
+        Plugin.LogProxy.Info($"[Pin] Rehydrate scan: {pinned} pinned tab(s) found");
+
         foreach (var tab in Plugin.Config.Tabs)
         {
             if (!TabLifecycleHelpers.IsInPinnedPool(tab))
                 continue;
+
             if (tab.TellTarget is null || !tab.TellTarget.IsSet())
+            {
+                Plugin.LogProxy.Warning(
+                    $"[Pin] Pinned tab '{tab.Name}' has no usable TellTarget "
+                        + $"(Name={tab.TellTarget?.Name ?? "<null>"} World={tab.TellTarget?.World ?? 0}). "
+                        + "Chat input on this tab will be empty until the partner sends a tell or you /tell manually."
+                );
                 continue;
+            }
 
             tab.Channel ??= InputChannel.Tell;
             tab.CurrentChannel.Channel = InputChannel.Tell;
             tab.CurrentChannel.TellTarget = tab.TellTarget.Clone();
+
+            // MessageList is NonSerialized so pinned tabs come back empty.
+            // Preload the same history window the spawn path uses so the user
+            // sees the recent conversation, not a blank tab.
+            PreloadHistory(tab, tab.TellTarget.Name, tab.TellTarget.World, Guid.Empty);
+
+            Plugin.LogProxy.Info(
+                $"[Pin] Rehydrated '{tab.Name}' -> Tell target {tab.TellTarget.Name}@{tab.TellTarget.World}"
+            );
         }
     }
 
@@ -436,6 +456,9 @@ internal sealed class AutoTellTabsService : IDisposable
     {
         if (!tab.IsTempTab || tab.IsPinned)
         {
+            Plugin.LogProxy.Info(
+                $"[Pin] TryPin skipped: IsTempTab={tab.IsTempTab} IsPinned={tab.IsPinned}"
+            );
             return false;
         }
 
@@ -449,6 +472,9 @@ internal sealed class AutoTellTabsService : IDisposable
         }
 
         tab.IsPinned = true;
+        Plugin.LogProxy.Info(
+            $"[Pin] Pinned tab '{tab.Name}' target={tab.TellTarget?.Name}@{tab.TellTarget?.World}"
+        );
         _plugin.SaveConfig();
         return true;
     }
@@ -469,6 +495,7 @@ internal sealed class AutoTellTabsService : IDisposable
         }
 
         tab.IsPinned = false;
+        Plugin.LogProxy.Info($"[Pin] Unpinned tab '{tab.Name}'");
         _plugin.SaveConfig();
     }
 
@@ -482,6 +509,9 @@ internal sealed class AutoTellTabsService : IDisposable
         tab.IsTempTab = false;
         tab.IsPinned = false;
         tab.TellTarget = TellTarget.Empty();
+        Plugin.LogProxy.Info(
+            $"[Pin] Promoted tab '{tab.Name}' to permanent (tell-binding dropped)"
+        );
         _plugin.SaveConfig();
     }
 }