feat(ui): add SymbolPicker popup with FFXIV icon tab

New popup attached to the chat input lets the user browse and insert
Dalamud SeIconChar glyphs (161 PUA codepoints, server-safe by design).
Search field filters by enum name. Multi-insert keeps the popup open
until the user clicks elsewhere. BMP tab follows in the next commit.

HellionChat/Ui/ChatLogWindow.cs

@@ -40,6 +40,7 @@ public sealed class ChatLogWindow : Window
 
     private readonly CommandWrapper _clearHellionCommand;
     private readonly CommandWrapper _hellionCommand;
+    private readonly SymbolPicker _symbolPicker;
 
     internal bool ScreenshotMode;
     private string Salt { get; }
@@ -129,6 +130,8 @@ public sealed class ChatLogWindow : Window
         _clearHellionCommand.Execute += ClearLog;
         _hellionCommand.Execute += ToggleChat;
 
+        _symbolPicker = new SymbolPicker();
+
         Plugin.ClientState.Login += Login;
         Plugin.ClientState.Logout += Logout;
 
@@ -792,6 +795,30 @@ public sealed class ChatLogWindow : Window
         )
             inputColour = ecColour;
 
+        // Symbol-picker trigger sits left of the channel indicator. ImRaii.Popup
+        // inside DrawAndConsume pins to the last rendered item, so the call MUST
+        // run immediately after this IconButton — placing it after the channel
+        // picker below would pin the popup under the wrong widget.
+        if (ImGuiUtil.IconButton(
+                FontAwesomeIcon.Smile,
+                "symbol-picker-trigger",
+                "Insert symbol or FFXIV icon"))
+        {
+            _symbolPicker.OpenPopup();
+        }
+        var insertedSymbol = _symbolPicker.DrawAndConsume();
+        if (insertedSymbol is not null)
+        {
+            // Same cursor-aware splice idiom as the AutoComplete commit path at
+            // ChatLogWindow.cs:2487-2493. Clamp because CursorPos can drift if
+            // the user mutates Chat while the popup is open.
+            var pos = Math.Clamp(CursorPos, 0, Chat.Length);
+            Chat = Chat[..pos] + insertedSymbol + Chat[pos..];
+            Activate = true;
+            ActivatePos = pos + insertedSymbol.Length;
+        }
+        ImGui.SameLine();
+
         var beforeIcon = ImGui.GetCursorPos();
 
         var tintSelector = Plugin.Config.ColorSelectedInputChannelButton && inputColour.HasValue;

HellionChat/Ui/SymbolPicker.cs

@@ -0,0 +1,124 @@
+using System.Numerics;
+using Dalamud.Bindings.ImGui;
+using Dalamud.Game.Text;
+using Dalamud.Interface.Utility.Raii;
+
+namespace HellionChat.Ui;
+
+// Popup picker for chat-input symbol insertion. Two tabs:
+//   PUA  — Dalamud's SeIconChar enum (161 server-safe FFXIV glyphs)
+//   BMP  — server-verified Unicode symbols (whitelist built 2026-05-XX)
+//
+// Render-only — the Settings-Guard for showing the trigger button lives on
+// the caller side (ChatLogWindow). Recent-Used is session state by design.
+internal sealed class SymbolPicker
+{
+    private const string PopupId = "HellionSymbolPicker";
+    private const int RecentCapacity = 16;
+
+    private string _search = string.Empty;
+    private readonly List<uint> _recentUsed = new(capacity: RecentCapacity);
+
+    public void OpenPopup() => ImGui.OpenPopup(PopupId);
+
+    // Returns the inserted codepoint as a string fragment if the user clicked
+    // one this frame, or null otherwise. Caller splices the fragment into the
+    // chat-input buffer at the current cursor position.
+    public string? DrawAndConsume()
+    {
+        // ImRaii.Popup mirrors ChatLogWindow.cs:823 / :2380, PayloadHandler.cs:68
+        // — auto-EndPopup via using-Dispose.
+        using var popup = ImRaii.Popup(PopupId);
+        if (!popup)
+            return null;
+
+        string? inserted = null;
+
+        using (var tabs = ImRaii.TabBar("##symbolpicker-tabs"))
+        {
+            if (tabs)
+            {
+                inserted = DrawPuaTab() ?? inserted;
+                inserted = DrawBmpTab() ?? inserted;
+            }
+        }
+
+        if (inserted is not null)
+            TrackRecent(inserted);
+
+        return inserted;
+    }
+
+    private string? DrawPuaTab()
+    {
+        using var tab = ImRaii.TabItem("FFXIV Icons");
+        if (!tab)
+            return null;
+
+        ImGui.InputTextWithHint("##pua-search", "Search by name (e.g. HighQuality)", ref _search, 64);
+
+        string? inserted = null;
+
+        if (ImGui.BeginChild("##pua-grid", new Vector2(0, 280), false))
+        {
+            var query = _search;
+            foreach (var icon in Enum.GetValues<SeIconChar>())
+            {
+                var label = icon.ToString();
+                if (query.Length > 0
+                    && label.IndexOf(query, StringComparison.OrdinalIgnoreCase) < 0)
+                {
+                    continue;
+                }
+
+                // ToIconString() returns the single-codepoint string ready for
+                // ImGui rendering (Dalamud SeIconCharExtensions.cs:25). Tooltip
+                // carries the enum name so users can discover what each glyph
+                // means.
+                if (ImGui.Selectable(
+                        icon.ToIconString(),
+                        false,
+                        ImGuiSelectableFlags.DontClosePopups,
+                        new Vector2(24, 24)))
+                {
+                    inserted = icon.ToIconString();
+                }
+                if (ImGui.IsItemHovered())
+                    ImGui.SetTooltip(label);
+
+                // Manually-wrapping pattern from imgui_demo.cpp on modern API.
+                // GetWindowContentRegionMax is obsolete since ImGui 1.92
+                // (imgui.h:565); HellionChat uses GetContentRegionAvail
+                // throughout (e.g. ChatLogWindow.cs:840). Same modern idiom.
+                var style = ImGui.GetStyle();
+                var lastItemX2 = ImGui.GetItemRectMax().X;
+                var availableRightX =
+                    ImGui.GetCursorScreenPos().X + ImGui.GetContentRegionAvail().X;
+                if (lastItemX2 + style.ItemSpacing.X + 24f < availableRightX)
+                    ImGui.SameLine();
+            }
+        }
+        ImGui.EndChild();
+
+        return inserted;
+    }
+
+    // Task 5 wires the BMP whitelist; the stub keeps the popup contract intact
+    // until then.
+    private string? DrawBmpTab() => null;
+
+    private void TrackRecent(string fragment)
+    {
+        if (string.IsNullOrEmpty(fragment) || fragment.Length > 4)
+            return;
+
+        var codepoint = (uint)char.ConvertToUtf32(fragment, 0);
+
+        // Move-to-front so the head stays the freshest pick.
+        _recentUsed.RemoveAll(c => c == codepoint);
+        _recentUsed.Insert(0, codepoint);
+
+        if (_recentUsed.Count > RecentCapacity)
+            _recentUsed.RemoveAt(_recentUsed.Count - 1);
+    }
+}