Get Exponential Moving Average for trend analysis

Returns EMA indicator data optimized for AI trading signals, more responsive than SMA and sampled to 200 points for efficient trend detection. Preferred EMA tool — the /ta/{slug}/ema and /ta/{slug}/ema/latest variants are legacy; use this, or /ta/{slug}/allLatest for all indicators in one call. Subject to the shared TA rate pool; for many assets prefer /agentFriendly/full_assets_by_slug with includeTaData=true.