Enable file logging by default (#119)

* Initial plan

* feat: enable file logging by default on first launch

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Co-authored-by: MaximumTrainer <1376575+MaximumTrainer@users.noreply.github.com>

* test: make testConfig_fileLoggingEnabledByDefault exercise loadConfig() with RAII guards

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Co-authored-by: MaximumTrainer <1376575+MaximumTrainer@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: MaximumTrainer <1376575+MaximumTrainer@users.noreply.github.com>

Author: Copilot

README.md

@@ -300,7 +300,8 @@ You need Qt Linguist to open and generate a new language file (`.qm` file).
 ## Log Files
 
 MaximumTrainer writes diagnostic messages (network errors, BLE events, OAuth login steps) to a log
-file when file logging is enabled. Enable it in **Preferences → Preferences & Profile → Logging**.
+file. File logging is **enabled by default** on first launch; you can adjust the level or disable it
+in **Preferences → Preferences & Profile → Logging**.
 
 | Platform | Default log file path |
 |----------|-----------------------|

src/app/logger.cpp

@@ -141,7 +141,7 @@ void Logger::loadConfig()
     const int level = settings.value(QStringLiteral("level"),
                                      static_cast<int>(LogLevel::Info)).toInt();
     const bool fileOn = settings.value(QStringLiteral("file_enabled"),
-                                       false).toBool();
+                                       true).toBool();
     const QString fp  = settings.value(QStringLiteral("file_path"),
                                        QString()).toString();
     settings.endGroup();

src/app/logger.h

@@ -18,7 +18,7 @@
  *
  * Configuration is persisted via QSettings (group "logging"):
  *   logging/level        (int, default 2 = Info)
- *   logging/file_enabled (bool, default false)
+ *   logging/file_enabled (bool, default true)
  *   logging/file_path    (string, default <AppData>/MaximumTrainer.log)
  *
  * Quick-start:

tests/logger/tst_logger.cpp

@@ -17,6 +17,7 @@
 #include <QSettings>
 #include <QRegularExpression>
 #include <QDir>
+#include <QScopeGuard>
 
 #include "../../src/app/logger.h"
 
@@ -106,6 +107,7 @@ private slots:
 
     // ── Config round-trip ─────────────────────────────────────────────────────
     void testConfig_saveAndLoad();
+    void testConfig_fileLoggingEnabledByDefault();
 };
 
 // ─────────────────────────────────────────────────────────────────────────────
@@ -356,6 +358,48 @@ void TstLogger::testConfig_saveAndLoad()
     Logger::instance().setLogLevel(saved);
 }
 
+void TstLogger::testConfig_fileLoggingEnabledByDefault()
+{
+    // RAII guard: restore Logger's file-logging state unconditionally so that
+    // a QVERIFY failure in this test cannot leave the Logger in a broken state
+    // and cause subsequent tests to behave unexpectedly.
+    const bool savedEnabled = Logger::instance().isFileLoggingEnabled();
+    const QString savedPath = Logger::instance().logFilePath();
+    auto loggerGuard = qScopeGuard([&] {
+        Logger::instance().setFileLogging(savedEnabled, savedPath);
+    });
+
+    // RAII guard: remove (or restore) the logging/file_enabled QSettings key.
+    // This simulates a fresh install where no user preference has been saved.
+    QSettings settings;
+    settings.beginGroup(QStringLiteral("logging"));
+    const QVariant prevValue = settings.value(QStringLiteral("file_enabled"));
+    settings.remove(QStringLiteral("file_enabled"));
+    settings.endGroup();
+    settings.sync();
+
+    auto settingsGuard = qScopeGuard([&] {
+        QSettings s;
+        s.beginGroup(QStringLiteral("logging"));
+        if (prevValue.isValid())
+            s.setValue(QStringLiteral("file_enabled"), prevValue);
+        else
+            s.remove(QStringLiteral("file_enabled"));
+        s.endGroup();
+        s.sync();
+    });
+
+    // Start from a known-disabled state so we can detect whether
+    // loadConfig() actually enables file logging.
+    Logger::instance().setFileLogging(false);
+
+    // Exercise the real loadConfig() path — it must default to enabled.
+    Logger::instance().loadConfig();
+
+    QVERIFY2(Logger::instance().isFileLoggingEnabled(),
+             "loadConfig() must enable file logging when file_enabled is absent from settings");
+}
+
 // ─────────────────────────────────────────────────────────────────────────────
 // Test runner
 // ─────────────────────────────────────────────────────────────────────────────