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/services/rulesengine.h

@@ -0,0 +1,61 @@
+#pragma once
+
+#include "../db/dao/ruledao.h"
+#include "../db/dao/categorydao.h"
+#include "../db/dao/mailitemdao.h"
+#include "../db/dao/folderdao.h"
+#include <QVector>
+#include <QMap>
+#include <QJsonObject>
+#include <QJsonArray>
+#include <functional>
+
+class RulesEngine
+{
+public:
+    struct EvaluationContext
+    {
+        const MailItem* mailItem = nullptr;
+        qint64 folderId = -1;
+        qint64 accountId = -1;
+        QMap<QString, QVariant> variables;
+    };
+
+    struct ActionResult
+    {
+        bool success = false;
+        QString message;
+        QVariant data;
+    };
+
+    // Main evaluation entry point
+    static QVector<ActionResult> evaluateAndExecute(const EvaluationContext& ctx);
+
+    // Rule matching
+    static bool matchesConditions(const Rule& rule, const EvaluationContext& ctx);
+    static bool matchCondition(const RuleCondition& cond, const EvaluationContext& ctx);
+    static QString getFieldValue(const RuleCondition& cond, const EvaluationContext& ctx);
+
+    // Action execution
+    static ActionResult executeAction(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeMoveToFolder(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeMarkAsRead(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeMarkAsFlagged(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeDelete(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeAssignCategory(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeRemoveCategory(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeForwardTo(const RuleAction& action, const EvaluationContext& ctx);
+    static ActionResult executeSetPriority(const RuleAction& action, const EvaluationContext& ctx);
+
+    // Batch operations
+    static int runRulesOnFolder(qint64 folderId, qint64 accountId = -1);
+    static int runRulesOnMails(const QVector<qint64>& mailIds, qint64 accountId = -1);
+
+    // Callbacks for UI integration
+    using ProgressCallback = std::function<void(int processed, int total, const QString& currentRule)>;
+    static void setProgressCallback(ProgressCallback cb);
+
+private:
+    static ProgressCallback s_progressCallback;
+    static bool shouldStopProcessing(const RuleAction& action);
+};