feat: comprehensive Wino Mail updates

- ReaderView: complete rewrite with CSS styling, headers, attachments, zoom, find, dark mode, image blocking
- Categories: DAO + UI tree widget with colors, nested categories, assignment
- Rules engine: DAO + evaluation + actions (move, mark read, flag, delete, category, forward)
- Templates: DAO + editor + manager with variables support
- Signatures: DAO + manager + auto-per-account + manual selector in compose
- ComposeView: signature combo, template selector, auto-signature on new email
- MainWindow: frameless with rounded corners, 1px border, resize from edges, no status bar
- Database: new tables (Category, MailCategory, Rule, Template, Signature) with indexes

src/ui/readerview.h

@@ -7,6 +7,11 @@
 #include <QListWidget>
 #include <QVBoxLayout>
 #include <QHBoxLayout>
+#include <QToolButton>
+#include <QLineEdit>
+#include <QScrollArea>
+#include <QFrame>
+#include <QMenu>
 #include "core/mailitem.h"
 
 class ReaderView : public QWidget {
@@ -17,24 +22,81 @@ public:
     ~ReaderView() override = default;
 
     void setMailItem(const MailItem* item);
+    void setDarkMode(bool dark);
 
 signals:
-    void replyRequested(const MailItem* item);
-    void forwardRequested(const MailItem* item);
-    void deleteRequested(const MailItem* item);
+    void replyRequested(int mailId);
+    void forwardRequested(int mailId);
+    void deleteRequested(int mailId);
     void detachRequested();
+    void openAttachmentRequested(const QString &path);
 
+private slots:
+    void onReplyClicked();
+    void onForwardClicked();
+    void onDeleteClicked();
+    void onDetachClicked();
 
 private:
     void setupUI();
+    void setupBodyViewer();
+    void setupAttachmentsArea();
+    void setupFindBar();
+    void applyEmailCss();
+    void updateZoom();
+    void refreshCurrentMail();
+    QString sanitizeHtml(const QString &html);
+    QString formatAddress(const QString &raw);
+    QString formatDate(const QDateTime &dt);
+    QIcon mimeIcon(const QString &mimeType);
+    void showAttachmentContextMenu(const QPoint &pos, const QString &path, const QString &name);
 
+    // Header
+    QWidget *m_headerWidget;
+    QLabel *m_avatarLabel;
     QLabel *m_subjectLabel;
     QLabel *m_fromLabel;
     QLabel *m_dateLabel;
+    QLabel *m_toLabel;
+    
+    // Actions
+    QToolButton *m_replyButton;
+    QToolButton *m_forwardButton;
+    QToolButton *m_deleteButton;
+    QToolButton *m_detachButton;
+    QToolButton *m_moreButton;
+    
+    // Body
+    QScrollArea *m_scrollArea;
     QTextBrowser *m_bodyViewer;
+    QWidget *m_bodyContainer;
+    QVBoxLayout *m_bodyLayout;
+    qreal m_zoomFactor = 1.0;
+    
+    // Attachments
+    QFrame *m_attachmentsFrame;
+    QVBoxLayout *m_attachmentsLayout;
+    QLabel *m_attachmentsHeader;
     QListWidget *m_attachmentList;
     
-    QPushButton *m_replyButton;
-    QPushButton *m_forwardButton;
-    QPushButton *m_deleteButton;
+    // Find bar
+    QFrame *m_findBar;
+    QLineEdit *m_findInput;
+    QToolButton *m_findPrevButton;
+    QToolButton *m_findNextButton;
+    QToolButton *m_findCloseButton;
+    QLabel *m_findCountLabel;
+    
+    // Toolbar (zoom, etc.)
+    QFrame *m_toolbar;
+    QToolButton *m_zoomInButton;
+    QToolButton *m_zoomOutButton;
+    QToolButton *m_zoomResetButton;
+    QLabel *m_zoomLabel;
+    
+    int m_currentMailId = -1;
+    bool m_darkMode = false;
+    QString m_baseCss;
+    bool m_allowExternalImages = false;
+    QToolButton *m_loadImagesButton = nullptr;
 };