Run the full analysis pipeline according to the specified depth.
Returns the final AnalysisResult, optional ValidationResult, and
per-iteration timing data for audit metadata.
{ analysis, validation, iterationDurationsMs } where
validation is null for depth < 'deep' and iterationDurationsMs
contains one entry per completed iteration/validation pass.
Run the full analysis pipeline according to the specified depth. Returns the final AnalysisResult, optional ValidationResult, and per-iteration timing data for audit metadata.