Returns the ordered list of sections that make up the experiment (TEXT, FILE, SAMPLESIN, SAMPLESOUT, EQUIPMENT, etc.) along with their positions and section-type-specific metadata. By default only non-archived sections are returned — pass archived=true to include archived sections, or omit it to get the default. Use the type-specific content endpoints (e.g. GET /experiments/sections/{expJournalID}/content) to fetch each section's contents.