A long-only, single-instrument, single-timeframe strategy on ADAUSDT.BINANCE 4H bars (audit_stale issue now RESOLVED per analyst feedback). Implements a NEW STRUCTURAL MECHANISM consistent with the analyst's explicit guidance: 'STRUCTURAL signals (sequence-based or range-statistics-based) are what work on liquid crypto.' The mechanism: DONCHIAN CHANNEL-MIDPOINT RECLAIM. Compute the 20-bar Donchian channel midpoint (average of high20 and low20). When price has been BELOW the midpoint for at least 3 consecutive bars (price was in the lower half of the range — sellers controlled the range) and then the current bar CLOSES BACK ABOVE the midpoint by at least 0.2×ATR (decisive reclaim, not noise), this signals a structural shift back to buyer control within the established range. Combined with a long-term uptrend filter (close > sma_100), this captures the moment when price recovery within range aligns with broader trend. Critically distinct from every existing ADA 4H mechanism: (a) NOT Donchian high/low breach (uses MIDPOINT, not channel boundary); (b) NOT double-low support (uses INTRA-RANGE midpoint pivot, not low-level matching); (c) NOT failed-breakdown reclaim (different reference: midpoint not low); (d) NOT channel-WIDTH expansion (uses midpoint as price reference, not range size); (e) NOT cumulative return / z-score / autocorrelation (no statistical-magnitude math — pure structural price-level signal); (f) NOT volume signal. STRUCTURAL + RANGE-STATISTICS-BASED per analyst's explicit recommendation. Three filters only.