TASK 20 step 2: hotkey config UI + modifier chord persistence + conflict detection

Services/LayoutStore.cs

@@ -1220,6 +1220,57 @@ public class LayoutStore : IDisposable
             meta.ScheduledStartTime?.ToString("o") ?? string.Empty);
     }
 
+    // ─── Hotkey bindings (TASK 20 step 2) ───
+
+    /// <summary>
+    /// Load saved hotkey bindings. Returns only entries that have been explicitly
+    /// saved — missing HotkeyIds are unbound (not in the returned dictionary).
+    /// Caller fills in defaults for any missing entries as needed.
+    /// </summary>
+    public Dictionary<HotkeyId, HotkeyChord> LoadHotkeyBindings()
+    {
+        var result = new Dictionary<HotkeyId, HotkeyChord>();
+        foreach (HotkeyId id in Enum.GetValues(typeof(HotkeyId)))
+        {
+            var raw = GetSetting($"Hotkey.{id}");
+            if (raw == null) continue; // not saved = unbound
+            if (raw == "none") continue; // explicitly unbound
+            try
+            {
+                result[id] = HotkeyChord.ParseStorage(raw);
+            }
+            catch (FormatException)
+            {
+                // corrupt entry — skip, will fall back to default
+            }
+        }
+        return result;
+    }
+
+    /// <summary>
+    /// Save hotkey bindings. Null entries in the dictionary mean "unbound" (stored
+    /// as "none"). Only the provided entries are saved; previously saved entries
+    /// for HotkeyIds not in the dictionary are deleted.
+    /// </summary>
+    public void SaveHotkeyBindings(Dictionary<HotkeyId, HotkeyChord?> bindings)
+    {
+        // Delete all existing hotkey settings first
+        foreach (HotkeyId id in Enum.GetValues(typeof(HotkeyId)))
+        {
+            using var cmd = _connection.CreateCommand();
+            cmd.CommandText = "DELETE FROM Settings WHERE Key = $key;";
+            cmd.Parameters.AddWithValue("$key", $"Hotkey.{id}");
+            cmd.ExecuteNonQuery();
+        }
+
+        // Save the new bindings
+        foreach (var (id, chord) in bindings)
+        {
+            var value = chord?.ToString() ?? "none";
+            UpsertSetting($"Hotkey.{id}", value);
+        }
+    }
+
     public (double Left, double Top, double Width, double Height, string State)? LoadWindowState()
     {
         var left = GetSetting("Window.Left");