Add a new configuration option to QDoc that enables writing all warning messages to a dedicated log file for easier tracking and analysis.

Current Situation

• QDoc warnings are only written to stderr
• Difficult to collect and analyze warnings in CI/CD pipelines
• No persistent record of warnings for tracking documentation quality over time

Proposed Solution

Implement a logwarnings configuration option that, when enabled, makes QDoc write all warnings to a log file while maintaining the existing stderr output.

Requirements

• Add logwarnings boolean configuration option.
• When enabled, create log file: {{ {project}

  -qdoc-warnings.log}} in output directory.

• Log file should include:
  • QDoc command line arguments at the top.
  • All warning messages generated during the run.
• Create output directory if it doesn't exist.
• Maintain existing stderr output (warnings appear in both places).
• Handle file creation errors gracefully.

Acceptance Criteria

• logwarnings=true in config creates a warning log file.
• logwarnings=false or unset maintains current behavior (no log file).
• Log file contains command line and all warnings.
• Warnings still appear on stderr.
• No performance impact when feature is disabled.

Benefits

• Easier warning collection in CI/CD pipelines.
• Track documentation quality metrics over time.
• Simplify debugging of documentation issues.
• Enable automated warning analysis and reporting.