feat(qml): task #16 历史记录 tab 完整重做（ListView + 详情面板）

core/history.py:
  HistoryListModel.roleNames() 暴露 4 个 Qt 内置 role 给 QML：
  display / decoration / toolTip / timestamp (UserRole)
  旧 QListView 用 int role 不受影响

bridges/history.py:
  Slot thumbnailPath(timestamp) → str
  返回 thumb.jpg 本地路径（按需用 PIL 生成 240px JPEG），缩略图缺失回退原图

qml_poc/qml/HistoryTab.qml (新):
  - 左侧 340px 卡片：列表 (history.model)
    * delegate 76px 高：60×60 缩略图 + timestamp + prompt 双行摘要
    * 选中态 accent 蓝边框 + accentSubtle 浅蓝底
    * hover 提示完整 toolTip
  - 右侧详情卡片：
    * timestamp + createdAt + "在文件管理器中打开" + "删除"
    * 360px 大图（双击系统查看器打开）
    * GridLayout 4 列元信息（宽高比/尺寸/模型）
    * prompt ScrollView（长文本可滚）
  - Component.onCompleted + onCountChanged 自动选中第一条
  - itemRemoved 信号 → 选中失效时回到空态

qml_poc/main_qml.py:
  AppState 加 QML_DEBUG_TAB env var (0/1/2) 控制启动 tab 索引，方便 PoC 调试

MainWindow.qml: 历史记录占位 Item → HistoryTab {}

视觉验证：QML_DEBUG_TAB=2 直接进历史 tab，2 条已存历史正确渲染（缩略图 +
详情大图 + 元信息 + prompt 都对），UI 无回归。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

@@ -83,3 +83,15 @@ class HistoryBridge(QObject):
             "model": item.model,
             "createdAt": item.created_at.strftime("%Y-%m-%d %H:%M:%S"),
         }
+
+    @Slot(str, result=str)
+    def thumbnailPath(self, timestamp: str) -> str:
+        """返回该 timestamp 缩略图本地路径（按需生成）。源图缺失时返回 ""。"""
+        item = self._history.load_history_item_fast(timestamp)
+        if item is None or not item.generated_image_path.exists():
+            return ""
+        thumb = self._history.get_or_create_thumbnail(item.generated_image_path)
+        if thumb is None:
+            # 缩略图生成失败时回退到原图（QML Image 读 PNG 没问题）
+            return str(item.generated_image_path)
+        return str(thumb)

@@ -85,6 +85,19 @@ class HistoryListModel(QAbstractListModel):
             return 0
         return len(self._timestamps)
 
+    def roleNames(self):
+        """暴露 Qt 内置 roles 给 QML（默认 QML 只能 model.display）。
+
+        QListView (旧 QWidget UI) 用 int role 不受影响；QML ListView delegate
+        现在能用 model.timestamp / model.toolTip 等访问。
+        """
+        return {
+            Qt.DisplayRole: b"display",
+            Qt.DecorationRole: b"decoration",
+            Qt.ToolTipRole: b"toolTip",
+            Qt.UserRole: b"timestamp",
+        }
+
     def flags(self, index: QModelIndex):
         if not index.isValid():
             return Qt.NoItemFlags

@@ -54,6 +54,10 @@ class AppState(QObject):
         self._auth = auth_bridge
         # 兼容现有 QML：env QML_AUTO_LOGIN=1 时强制 loggedIn=True
         self._poc_force_login = os.environ.get("QML_AUTO_LOGIN", "") == "1"
+        # 调试便捷：env QML_DEBUG_TAB=0/1/2 控制启动时默认 tab
+        try:
+            self._current_tab = int(os.environ.get("QML_DEBUG_TAB", "0"))
+        except ValueError:
             self._current_tab = 0
         self._auth.loggedInChanged.connect(self.loggedInChanged.emit)
 

+import QtQuick
+import QtQuick.Controls.Basic
+import QtQuick.Layouts
+import "components"
+import "." as App
+
+Item {
+    id: tab
+
+    property string selectedTimestamp: ""
+    property var selectedItem: ({})
+
+    function selectTimestamp(ts) {
+        if (!ts) {
+            tab.selectedTimestamp = ""
+            tab.selectedItem = ({})
+            return
+        }
+        tab.selectedTimestamp = ts
+        tab.selectedItem = history.getItem(ts) || ({})
+    }
+
+    // 列表数据变化时校正选中项
+    Connections {
+        target: history
+        function onItemRemoved(ts) {
+            if (tab.selectedTimestamp === ts) tab.selectTimestamp("")
+        }
+        function onCountChanged() {
+            // 自动选中第一条（首次加载 / 新增时）
+            if (tab.selectedTimestamp === "" && historyList.count > 0) {
+                var idx = historyList.model.index(0, 0)
+                var ts = historyList.model.data(idx, Qt.UserRole)
+                if (ts) tab.selectTimestamp(ts)
+            }
+        }
+    }
+
+    Component.onCompleted: {
+        if (historyList.count > 0) {
+            var idx = historyList.model.index(0, 0)
+            var ts = historyList.model.data(idx, Qt.UserRole)
+            if (ts) tab.selectTimestamp(ts)
+        }
+    }
+
+    RowLayout {
+        anchors.fill: parent
+        anchors.margins: App.Theme.space5
+        spacing: App.Theme.space4
+
+        // ===== 左侧：列表 =====
+        Card {
+            Layout.preferredWidth: 340
+            Layout.fillHeight: true
+
+            ColumnLayout {
+                anchors.fill: parent
+                anchors.margins: App.Theme.space4
+                spacing: App.Theme.space3
+
+                RowLayout {
+                    spacing: App.Theme.space3
+                    CaptionLabel {
+                        text: "历史记录"
+                        font.pointSize: App.Theme.fontLg
+                    }
+                    Label {
+                        text: history.count + " 条"
+                        font.family: App.Theme.fontFamily
+                        font.pointSize: App.Theme.fontSm
+                        color: App.Theme.textSecondary
+                    }
+                    Item { Layout.fillWidth: true }
+                    SecondaryButton {
+                        text: "刷新"
+                        onClicked: history.refresh()
+                    }
+                }
+
+                // 空态
+                Label {
+                    visible: historyList.count === 0
+                    Layout.fillWidth: true
+                    Layout.fillHeight: true
+                    horizontalAlignment: Text.AlignHCenter
+                    verticalAlignment: Text.AlignVCenter
+                    text: "暂无历史记录\n生成图片后会自动出现在这里"
+                    font.family: App.Theme.fontFamily
+                    font.pointSize: App.Theme.fontSm
+                    color: App.Theme.textTertiary
+                }
+
+                ListView {
+                    id: historyList
+                    Layout.fillWidth: true
+                    Layout.fillHeight: true
+                    visible: count > 0
+                    spacing: 4
+                    clip: true
+                    model: history.model
+
+                    delegate: Rectangle {
+                        required property int index
+                        required property string display
+                        required property string toolTip
+                        required property string timestamp
+
+                        width: ListView.view.width
+                        height: 76
+                        radius: App.Theme.radiusSm
+                        color: tab.selectedTimestamp === timestamp ? App.Theme.accentSubtle
+                             : itemMouse.containsMouse                ? App.Theme.bgHover
+                             : "transparent"
+                        border.width: tab.selectedTimestamp === timestamp ? 1 : 0
+                        border.color: App.Theme.accent
+
+                        RowLayout {
+                            anchors.fill: parent
+                            anchors.margins: App.Theme.space2
+                            spacing: App.Theme.space3
+
+                            // 缩略图
+                            Rectangle {
+                                Layout.preferredWidth: 60
+                                Layout.preferredHeight: 60
+                                radius: App.Theme.radiusSm
+                                color: App.Theme.bgSubtle
+
+                                Image {
+                                    id: thumb
+                                    anchors.fill: parent
+                                    anchors.margins: 1
+                                    source: {
+                                        var p = history.thumbnailPath(timestamp)
+                                        return p ? "file:///" + p : ""
+                                    }
+                                    fillMode: Image.PreserveAspectCrop
+                                    smooth: true
+                                    asynchronous: true
+                                }
+                            }
+
+                            // 文字
+                            ColumnLayout {
+                                Layout.fillWidth: true
+                                Layout.fillHeight: true
+                                spacing: 2
+
+                                Text {
+                                    Layout.fillWidth: true
+                                    text: timestamp
+                                    color: App.Theme.textPrimary
+                                    font.family: App.Theme.fontFamily
+                                    font.pointSize: App.Theme.fontXs
+                                    font.weight: Font.DemiBold
+                                }
+                                Text {
+                                    Layout.fillWidth: true
+                                    text: display.split("\n").slice(1).join(" ")
+                                    color: App.Theme.textSecondary
+                                    font.family: App.Theme.fontFamily
+                                    font.pointSize: App.Theme.fontXs
+                                    elide: Text.ElideRight
+                                    maximumLineCount: 2
+                                    wrapMode: Text.Wrap
+                                }
+                            }
+                        }
+
+                        MouseArea {
+                            id: itemMouse
+                            anchors.fill: parent
+                            hoverEnabled: true
+                            cursorShape: Qt.PointingHandCursor
+                            onClicked: tab.selectTimestamp(timestamp)
+                        }
+
+                        ToolTip.text: toolTip
+                        ToolTip.visible: itemMouse.containsMouse && toolTip.length > 0
+                        ToolTip.delay: 600
+                    }
+                }
+            }
+        }
+
+        // ===== 右侧：详情 =====
+        Card {
+            Layout.fillWidth: true
+            Layout.fillHeight: true
+
+            // 空态
+            Label {
+                anchors.centerIn: parent
+                visible: tab.selectedTimestamp === ""
+                text: "选择左侧记录查看详情"
+                font.family: App.Theme.fontFamily
+                font.pointSize: App.Theme.fontSm
+                color: App.Theme.textTertiary
+            }
+
+            ColumnLayout {
+                visible: tab.selectedTimestamp !== ""
+                anchors.fill: parent
+                anchors.margins: App.Theme.space4
+                spacing: App.Theme.space3
+
+                // header: 时间 + 操作按钮
+                RowLayout {
+                    Layout.fillWidth: true
+                    spacing: App.Theme.space3
+
+                    CaptionLabel {
+                        text: tab.selectedItem.timestamp || ""
+                        font.pointSize: App.Theme.fontLg
+                    }
+                    Label {
+                        text: tab.selectedItem.createdAt || ""
+                        font.family: App.Theme.fontFamily
+                        font.pointSize: App.Theme.fontSm
+                        color: App.Theme.textSecondary
+                    }
+                    Item { Layout.fillWidth: true }
+                    SecondaryButton {
+                        text: "在文件管理器中打开"
+                        onClicked: {
+                            if (tab.selectedItem.generatedImagePath) {
+                                Qt.openUrlExternally("file:///" + tab.selectedItem.generatedImagePath)
+                            }
+                        }
+                    }
+                    SecondaryButton {
+                        text: "删除"
+                        onClicked: {
+                            if (tab.selectedTimestamp) {
+                                history.deleteItem(tab.selectedTimestamp)
+                            }
+                        }
+                    }
+                }
+
+                // 大图
+                Rectangle {
+                    Layout.fillWidth: true
+                    Layout.preferredHeight: 360
+                    color: App.Theme.bgSubtle
+                    radius: App.Theme.radiusMd
+
+                    Image {
+                        anchors.fill: parent
+                        anchors.margins: App.Theme.space3
+                        source: tab.selectedItem.generatedImagePath
+                            ? "file:///" + tab.selectedItem.generatedImagePath
+                            : ""
+                        fillMode: Image.PreserveAspectFit
+                        smooth: true
+                        asynchronous: true
+
+                        MouseArea {
+                            anchors.fill: parent
+                            cursorShape: Qt.PointingHandCursor
+                            onDoubleClicked: {
+                                if (tab.selectedItem.generatedImagePath) {
+                                    Qt.openUrlExternally("file:///" + tab.selectedItem.generatedImagePath)
+                                }
+                            }
+                        }
+                    }
+                }
+
+                // 元信息
+                GridLayout {
+                    Layout.fillWidth: true
+                    columns: 4
+                    columnSpacing: App.Theme.space4
+                    rowSpacing: App.Theme.space2
+
+                    CaptionLabel { text: "宽高比" }
+                    Label {
+                        text: tab.selectedItem.aspectRatio || "—"
+                        font.family: App.Theme.fontFamily
+                        font.pointSize: App.Theme.fontSm
+                        color: App.Theme.textPrimary
+                    }
+                    CaptionLabel { text: "尺寸" }
+                    Label {
+                        text: tab.selectedItem.imageSize || "—"
+                        font.family: App.Theme.fontFamily
+                        font.pointSize: App.Theme.fontSm
+                        color: App.Theme.textPrimary
+                    }
+
+                    CaptionLabel { text: "模型" }
+                    Label {
+                        Layout.columnSpan: 3
+                        text: tab.selectedItem.model || "—"
+                        font.family: App.Theme.fontFamily
+                        font.pointSize: App.Theme.fontSm
+                        color: App.Theme.textPrimary
+                        elide: Text.ElideRight
+                        Layout.fillWidth: true
+                    }
+                }
+
+                // prompt
+                CaptionLabel { text: "提示词" }
+                ScrollView {
+                    Layout.fillWidth: true
+                    Layout.preferredHeight: 80
+                    Rectangle {
+                        anchors.fill: parent
+                        color: App.Theme.bgSubtle
+                        radius: App.Theme.radiusMd
+                        Text {
+                            anchors.fill: parent
+                            anchors.margins: App.Theme.space3
+                            text: tab.selectedItem.prompt || ""
+                            color: App.Theme.textPrimary
+                            font.family: App.Theme.fontFamily
+                            font.pointSize: App.Theme.fontSm
+                            wrapMode: Text.Wrap
+                        }
+                    }
+                }
+
+                Item { Layout.fillHeight: true }
+            }
+        }
+    }
+}

@@ -107,17 +107,7 @@ Rectangle {
                     }
                 }
 
-                // 历史记录 — 占位
-                Item {
-                    Text {
-                        anchors.centerIn: parent
-                        text: "历史记录 tab 内容\n(QML PoC 暂未实现)"
-                        color: App.Theme.textTertiary
-                        font.family: App.Theme.fontFamily
-                        font.pointSize: App.Theme.fontLg
-                        horizontalAlignment: Text.AlignHCenter
-                    }
-                }
+                HistoryTab {}
             }
         }