Unified logging: Replace LogSystem with EditorConsoleSink

- Created EditorConsoleSink (implements ILogSink interface)
- EditorConsoleSink stores logs in memory buffer (max 1000 entries)
- Added to Debug::Logger in Application::Initialize()
- ConsolePanel now reads from EditorConsoleSink via static GetInstance()
- Removed separate LogSystem singleton
- Removed editor/src/Core/LogEntry.h (no longer needed)

Now Editor and Engine share the same Debug::Logger, with ConsolePanel
displaying logs via EditorConsoleSink.

editor/src/Core/EditorConsoleSink.cpp

@@ -0,0 +1,43 @@
+#include "Core/EditorConsoleSink.h"
+
+namespace XCEngine {
+namespace Debug {
+
+EditorConsoleSink* EditorConsoleSink::GetInstance() {
+    static EditorConsoleSink instance;
+    return &instance;
+}
+
+EditorConsoleSink::EditorConsoleSink() = default;
+
+EditorConsoleSink::~EditorConsoleSink() = default;
+
+void EditorConsoleSink::Log(const LogEntry& entry) {
+    std::lock_guard<std::mutex> lock(m_mutex);
+    if (m_logs.size() >= MAX_LOGS) {
+        m_logs.erase(m_logs.begin());
+    }
+    m_logs.push_back(entry);
+    if (m_callback) {
+        m_callback();
+    }
+}
+
+void EditorConsoleSink::Flush() {
+}
+
+const std::vector<LogEntry>& EditorConsoleSink::GetLogs() const {
+    return m_logs;
+}
+
+void EditorConsoleSink::Clear() {
+    std::lock_guard<std::mutex> lock(m_mutex);
+    m_logs.clear();
+}
+
+void EditorConsoleSink::SetCallback(std::function<void()> callback) {
+    m_callback = std::move(callback);
+}
+
+} // namespace Debug
+} // namespace XCEngine