Logging and diagnostics improvements (#941)

Core logging and system diagnostics improvements, extracted from the compute branch.

### Logging
- **Elapsed timestamps**: Console log now shows elapsed time since launch `[HH:MM:SS.mmm]` instead of full date/time; file logging is unchanged
- **Short level names**: 3-letter short level names (`trc`/`dbg`/`inf`/`wrn`/`err`/`crt`) used by both console and file formatters via `ShortToStringView()`
- **Consistent field order**: Standardized to `[timestamp] [level] [logger]` across both console and file formatters
- **Slim LogMessage/LogPoint**: Remove redundant fields from `LogMessage` (derive level/source from `LogPoint`), flatten `LogPoint` to inline filename/line fields, shrink `LogLevel` to `int8_t` with `static_assert(sizeof(LogPoint) <= 32)`
- **Remove default member initializers** and static default `LogPoint` from `LogMessage` — all fields initialized by constructor
- **LoggerRef string constructor**: Convenience constructor accepting a string directly
- **Fix SendMessage macro collision**: Replace `thread.h` include in `logmsg.h` with a forward declaration of `GetCurrentThreadId()` to avoid pulling in `windows.h` transitively

### System Diagnostics
- **Cache static system metrics**: Add `RefreshDynamicSystemMetrics()` that only queries values that change at runtime (available memory, uptime, swap). `SystemMetricsTracker` snapshots full `GetSystemMetrics()` once at construction and reuses cached topology/total memory on each `Query()`, avoiding repeated `GetLogicalProcessorInformationEx` traversal on Windows, `/proc/cpuinfo` parsing on Linux, and `sysctl` topology calls on macOS

1 files changed, 28 insertions, 1 deletions

diff --git a/src/zencore/logging.cpp b/src/zencore/logging.cpp
index 5ada0cac7..ca34b7d0e 100644
--- a/src/zencore/logging.cpp
+++ b/src/zencore/logging.cpp
@@ -112,6 +112,14 @@ constinit std::string_view LevelNames[] = {std::string_view("trace", 5),
 										   std::string_view("critical", 8),
 										   std::string_view("off", 3)};
 
+constinit std::string_view ShortNames[] = {std::string_view("trc", 3),
+										   std::string_view("dbg", 3),
+										   std::string_view("inf", 3),
+										   std::string_view("wrn", 3),
+										   std::string_view("err", 3),
+										   std::string_view("crt", 3),
+										   std::string_view("off", 3)};
+
 LogLevel
 ParseLogLevelString(std::string_view Name)
 {
@@ -139,12 +147,27 @@ ParseLogLevelString(std::string_view Name)
 std::string_view
 ToStringView(LogLevel Level)
 {
+	using namespace std::literals;
+
 	if (int(Level) < LogLevelCount)
 	{
 		return LevelNames[int(Level)];
 	}
 
-	return "None";
+	return "None"sv;
+}
+
+std::string_view
+ShortToStringView(LogLevel Level)
+{
+	using namespace std::literals;
+
+	if (int(Level) < LogLevelCount)
+	{
+		return ShortNames[int(Level)];
+	}
+
+	return "None"sv;
 }
 
 }  // namespace zen::logging
@@ -476,6 +499,10 @@ LoggerRef::LoggerRef(logging::Logger& InLogger) : m_Logger(static_cast<logging::
 {
 }
 
+LoggerRef::LoggerRef(std::string_view LogCategory) : m_Logger(zen::logging::Get(LogCategory).m_Logger)
+{
+}
+
 void
 LoggerRef::Flush()
 {