초기 커밋: SheetMe 서식생성기 (P0~P5 완료 상태)

레거시 서식생성기(VB.NET WinForms) 대체용 C#/.NET 10 WPF 디자이너.
기준선: 실DB 활성 디자인 1,271건 왕복 의미론 diff 0 / 예외 0, 단위 테스트 49/49.

이 커밋에 함께 포함된 자격증명 분리:
- appsettings.json 을 __HOST__/__PASSWORD__ 플레이스홀더로 전환
- 실접속 정보는 appsettings.Development.json 으로 분리(.gitignore 제외,
  csproj Debug 조건부 복사라 Release 산출물에 실리지 않음)
- ConfigLoader 를 환경변수 > Development > appsettings 순 레이어링으로 변경,
  미치환 플레이스홀더는 '미설정'으로 간주

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/SheetMe.Designer/Views/FontManagerDialogView.xaml

@@ -0,0 +1,41 @@
+<Window x:Class="SheetMe.Designer.Views.FontManagerDialogView"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="폰트 일괄 변경" Width="620" Height="560" MinWidth="520" MinHeight="420"
+        WindowStartupLocation="CenterOwner" ShowInTaskbar="False">
+    <DockPanel Margin="12">
+        <TextBlock DockPanel.Dock="Top" Foreground="{DynamicResource B.Muted}" TextWrapping="Wrap" Margin="0,0,0,8"
+                   Text="문서 전체의 (타입·글꼴·크기) 조합입니다. 변경할 조합을 선택(다중 가능)하고 새 글꼴을 지정하세요."/>
+
+        <!-- 새 글꼴 지정 + 적용 -->
+        <Border DockPanel.Dock="Bottom" Background="{DynamicResource B.Chip}" CornerRadius="4" Padding="10" Margin="0,10,0,0">
+            <StackPanel>
+                <DockPanel>
+                    <TextBlock Text="새 글꼴" Width="60" VerticalAlignment="Center"/>
+                    <ComboBox x:Name="FamilyBox" IsEditable="True" Width="180" HorizontalAlignment="Left"/>
+                    <TextBlock Text="크기(pt)" Margin="14,0,6,0" VerticalAlignment="Center"/>
+                    <TextBox x:Name="SizeBox" Width="50" Text="9" VerticalContentAlignment="Center"/>
+                    <CheckBox x:Name="BoldBox" Content="굵게" Margin="14,0,0,0" VerticalAlignment="Center"/>
+                    <CheckBox x:Name="ItalicBox" Content="기울임" Margin="10,0,0,0" VerticalAlignment="Center"/>
+                    <CheckBox x:Name="UnderlineBox" Content="밑줄" Margin="10,0,0,0" VerticalAlignment="Center"/>
+                </DockPanel>
+                <DockPanel Margin="0,10,0,0">
+                    <Button DockPanel.Dock="Right" Content="닫기" Padding="16,4" Margin="8,0,0,0" IsCancel="True"/>
+                    <Button DockPanel.Dock="Right" Content="전체에 적용" Padding="14,4" Margin="8,0,0,0" Click="OnApplyAll"/>
+                    <Button DockPanel.Dock="Right" Content="선택 조합에 적용" Padding="14,4" Click="OnApplySelected"/>
+                    <TextBlock x:Name="ResultText" VerticalAlignment="Center" Foreground="{DynamicResource B.Success}"/>
+                </DockPanel>
+            </StackPanel>
+        </Border>
+
+        <!-- 집계 목록 -->
+        <ListBox x:Name="GroupList" SelectionMode="Extended" FontSize="13"
+                 ScrollViewer.HorizontalScrollBarVisibility="Disabled">
+            <ListBox.ItemTemplate>
+                <DataTemplate>
+                    <TextBlock Text="{Binding Display}" Margin="2"/>
+                </DataTemplate>
+            </ListBox.ItemTemplate>
+        </ListBox>
+    </DockPanel>
+</Window>