feat(factory): 内容工厂与链接处理

- 第三栏内容工厂：按拖入类型展示动作，动作按钮本身可接收 drop
- 链接分类：http(s) 按扩展名判定图片/音视频/文档/压缩包/网页
- http 链接动作：打开、下载、另存为、复制、Markdown、复制文件名、待办、问小埃
- 非标准 scheme：尝试打开、复制；thunder 解析 base64 真实地址，magnet 解析 dn
- 文字动作：ICU 分词、正则提取链接、朗读（spd-say）、复制、待办
- 文件/图片动作：打开、提取文字（占位）、生成描述、保存图片、复制路径、待办
- Downloader：异步下载到 XDG 下载目录 / 另存为，面板 toast 提示
- TodoModel：持久化到 todo.json，供「添加到待办」使用
- 无头自测 gxde-ai-see-selftest：链接分类/分词/提取链接/动作匹配
- 合成器 portal 自测脚本 tests/portal（虚拟指针 + GTK 源/目标）

src/factory/contentclassifier.cpp

@@ -0,0 +1,128 @@
+// SPDX-FileCopyrightText: 2026 GXDE OS Team
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "contentclassifier.h"
+
+#include <QFileInfo>
+#include <QImageReader>
+#include <QMimeData>
+#include <QUrl>
+
+namespace {
+
+QString extensionOfFile(const QString &path)
+{
+    return QFileInfo(path).suffix().toLower();
+}
+
+} // namespace
+
+QString DropContent::summary() const
+{
+    switch (kind) {
+    case Files: {
+        if (filePaths.size() == 1) {
+            const QFileInfo info(filePaths.first());
+            return QStringLiteral("文件 · %1").arg(info.fileName());
+        }
+        return QStringLiteral("%1 个文件").arg(filePaths.size());
+    }
+    case Image:
+        return QStringLiteral("图片");
+    case Text:
+        return QStringLiteral("文字 · %1 字").arg(text.size());
+    case Link:
+    case CustomLink: {
+        const QString label = link.fileType != QStringLiteral("page") && !link.fileType.isEmpty()
+                                  ? link.fileType
+                                  : link.kindLabel();
+        return link.displayName.isEmpty() ? label
+                                          : QStringLiteral("%1 · %2").arg(label, link.displayName);
+    }
+    default:
+        return QString();
+    }
+}
+
+namespace ContentClassifier {
+
+DropContent classifyText(const QString &text)
+{
+    DropContent content;
+    const QString trimmed = text.trimmed();
+    if (trimmed.isEmpty()) {
+        return content;
+    }
+
+    const LinkInfo info = LinkTools::parse(trimmed);
+    if (info.isValid()) {
+        content.kind = info.kind == LinkInfo::Http ? DropContent::Link : DropContent::CustomLink;
+        content.link = info;
+        content.text = trimmed;
+        return content;
+    }
+
+    content.kind = DropContent::Text;
+    content.text = text;
+    return content;
+}
+
+DropContent classify(const QMimeData *mime)
+{
+    DropContent content;
+    if (!mime) {
+        return content;
+    }
+
+    content.mimes = mime->formats();
+
+    if (mime->hasUrls()) {
+        QStringList localFiles;
+        LinkInfo link;
+        for (const QUrl &url : mime->urls()) {
+            if (url.isLocalFile()) {
+                localFiles.append(url.toLocalFile());
+            } else if (!link.isValid()) {
+                link = LinkTools::parseUrl(url);
+            }
+        }
+
+        if (!localFiles.isEmpty()) {
+            content.kind = DropContent::Files;
+            content.filePaths = localFiles;
+            if (localFiles.size() == 1) {
+                const QString suffix = extensionOfFile(localFiles.first());
+                if (LinkTools::fileTypeForExtension(suffix) == QStringLiteral("image") &&
+                    QImageReader(localFiles.first()).canRead()) {
+                    content.kind = DropContent::Image;
+                    content.image = QImage(localFiles.first());
+                }
+            }
+            return content;
+        }
+
+        if (link.isValid()) {
+            content.kind =
+                link.kind == LinkInfo::Http ? DropContent::Link : DropContent::CustomLink;
+            content.link = link;
+            content.text = link.url.toString();
+            return content;
+        }
+    }
+
+    if (mime->hasImage()) {
+        content.image = qvariant_cast<QImage>(mime->imageData());
+        if (!content.image.isNull()) {
+            content.kind = DropContent::Image;
+            return content;
+        }
+    }
+
+    if (mime->hasText()) {
+        return classifyText(mime->text());
+    }
+
+    return content;
+}
+
+} // namespace ContentClassifier