all: retry incomplete socket reads

Fixes greetd and hyprland ipc sockets reads being incomplete and
breaking said integrations on slow machines.

src/core/streamreader.hpp

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <qbytearray.h>
+#include <qiodevice.h>
+#include <qtypes.h>
+
+class StreamReader {
+public:
+	void setDevice(QIODevice* device);
+
+	void startTransaction();
+	QByteArray readBytes(qsizetype count);
+	QByteArray readUntil(char terminator);
+	void readInto(char* ptr, qsizetype count);
+	qint32 readI32();
+	bool commitTransaction();
+	void reset();
+
+private:
+	bool fill();
+
+	QIODevice* device = nullptr;
+	QByteArray buffer;
+	qsizetype cursor = 0;
+	bool failed = false;
+};