Performance for a TikTok advertiser account at campaign, ad group, ad or whole-advertiser level — spend, impressions, clicks, CTR, CPC, CPM and conversions by default, or whichever of TikTok’s metrics and grouping dimensions you name. `reportType` picks WHICH REPORT: BASIC is spend and performance (the default); AUDIENCE is the same money broken down by WHO SAW IT — pass an audience dimension such as age, gender, country_code or interest_category, which BASIC refuses outright. A report with ZERO rows genuinely means nothing delivered in that window — say exactly that, and never present zeros as measured performance. Read-only, free, spends nothing. NOTE: everything Hermoso creates on TikTok is created PAUSED, so a brand-new build reports nothing at all until somebody activates it with set_tiktok_ads_status(confirm:true) — check the statuses with list_tiktok_ads_campaigns before reading an empty report as bad performance.