[CrashReporting] Mock dialog, sentry skeleton and CI prerequisites

Mock: DlgCrashReport preview dialog (no account needed, redacted log
preview), CrashReportingMode Ask/Always/Never setting in DebugSettings,
--simulate-crash flag and Help-menu preview entry. Send writes a local
mock JSON only.

Vendor sentry-native 0.17.3 via FetchContent behind
WITH_CRASH_REPORTING (breakpad everywhere, backend none under
sanitizers) plus a CrashReporter facade with early init and post-loop
shutdown. DSN is a placeholder: empty CMake default with
COCKATRICE_SENTRY_DSN env override, so SDK init is skipped and mock
behavior is unchanged until a real DSN is configured.

CI prerequisites riding here so every layer below builds green:
libcurl dev plus CA bundles in the Linux images and CodeQL env, sentry
Qt integration off (its own find_package cannot see the macOS thin Qt
layout), and the StrFunc Using construction makensis requires.

Tests: ctest green, format clean, code plus UI gates PASS.

cockatrice/src/interface/widgets/dialogs/dlg_crash_report.h

@@ -0,0 +1,51 @@
+/**
+ * @file dlg_crash_report.h
+ * @ingroup Dialogs
+ */
+
+#ifndef DLG_CRASH_REPORT_H
+#define DLG_CRASH_REPORT_H
+
+#include <QDialog>
+#include <QString>
+#include <qtmetamacros.h>
+
+class QCheckBox;
+class QLabel;
+class QPlainTextEdit;
+class QPushButton;
+
+/**
+ * @brief MOCK crash-report dialog (UI + settings only, no network).
+ *
+ * The Send path writes a redacted JSON file to the temp dir instead of
+ * uploading anything. Real Sentry upload comes in a later phase.
+ */
+class DlgCrashReport : public QDialog
+{
+    Q_OBJECT
+public:
+    explicit DlgCrashReport(QWidget *parent = nullptr);
+
+    static QString buildRedactedPreview();
+    static QString writeMockReport(const QString &previewText);
+
+protected:
+    void changeEvent(QEvent *event) override;
+
+private:
+    QLabel *infoLabel;
+    QLabel *accountLabel;
+    QPlainTextEdit *previewArea;
+    QCheckBox *rememberBox;
+    QPushButton *sendButton;
+    QPushButton *dontSendButton;
+
+    void retranslateUi();
+
+private slots:
+    void actSend();
+    void actDontSend();
+};
+
+#endif