remove min_target_probability gate + add chart time-range presets

min_target_probability is gone: it filtered on the probability model the
calibration has repeatedly shown to be weak and overconfident, it was redundant
with the momentum gate, and as an off-by-default knob it just invited bad tuning.
Removed from the backend gate, activation config/schema, the frontend mirror
(qualifiesSetup / activationSummary), and ActivationSettings. The probability
model stays where it does real work (primary-target selection + display).

Charts: with multi-year history the all-bars default was unreadable. Added
time-range presets (1M / 3M / 6M / YTD / 1Y / 3Y / 5Y / All), defaulting to 1Y;
clicking a preset always re-applies (snaps back after a manual zoom). Y-axis
autoscale and wheel-zoom / drag-pan were already there.

339 backend tests pass; frontend build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/charts/CandlestickChart.tsx

@@ -51,6 +51,26 @@ interface TooltipState {
 
 const MIN_VISIBLE_BARS = 10;
 
+type RangePreset = '1M' | '3M' | '6M' | 'YTD' | '1Y' | '3Y' | '5Y' | 'All';
+const RANGE_PRESETS: RangePreset[] = ['1M', '3M', '6M', 'YTD', '1Y', '3Y', '5Y', 'All'];
+const PRESET_MONTHS: Record<string, number> = { '1M': 1, '3M': 3, '6M': 6, '1Y': 12, '3Y': 36, '5Y': 60 };
+const DEFAULT_PRESET: RangePreset = '1Y';
+
+/** First bar index to show for a time-range preset (data is ascending by date). */
+function startIndexForPreset(data: OHLCVBar[], preset: RangePreset): number {
+  if (preset === 'All' || data.length === 0) return 0;
+  const last = new Date(data[data.length - 1].date);
+  let cutoff: Date;
+  if (preset === 'YTD') {
+    cutoff = new Date(last.getFullYear(), 0, 1);
+  } else {
+    cutoff = new Date(last);
+    cutoff.setMonth(cutoff.getMonth() - PRESET_MONTHS[preset]);
+  }
+  const idx = data.findIndex((b) => new Date(b.date) >= cutoff);
+  return idx < 0 ? 0 : idx;
+}
+
 export function CandlestickChart({ data, srLevels = [], zones = [], tradeSetup, currentPrice }: CandlestickChartProps) {
   const canvasRef = useRef<HTMLCanvasElement>(null);
   const overlayCanvasRef = useRef<HTMLCanvasElement>(null);
@@ -67,11 +87,13 @@ export function CandlestickChart({ data, srLevels = [], zones = [], tradeSetup,
     start: 0,
     end: data.length,
   });
+  const [preset, setPreset] = useState<RangePreset>(DEFAULT_PRESET);
 
-  // Reset visible range when data changes
+  // Apply the active time-range preset when the data or preset changes (so the
+  // default view is a readable window, not the whole multi-year history).
   useEffect(() => {
-    setVisibleRange({ start: 0, end: data.length });
-  }, [data]);
+    setVisibleRange({ start: startIndexForPreset(data, preset), end: data.length });
+  }, [data, preset]);
 
   const draw = useCallback(() => {
     const canvas = canvasRef.current;
@@ -627,12 +649,33 @@ export function CandlestickChart({ data, srLevels = [], zones = [], tradeSetup,
   }
 
   return (
-    <div ref={containerRef} className="relative w-full" style={{ height: 400 }}>
-      <canvas
-        ref={canvasRef}
-        className="w-full"
-        style={{ height: 400 }}
-      />
+    <div className="w-full">
+      <div className="mb-2 flex flex-wrap items-center gap-1">
+        {RANGE_PRESETS.map((p) => (
+          <button
+            key={p}
+            type="button"
+            onClick={() => {
+              // Re-apply the range directly so clicking the active preset still
+              // snaps back after a manual wheel-zoom / pan.
+              setPreset(p);
+              setVisibleRange({ start: startIndexForPreset(data, p), end: data.length });
+            }}
+            className={`rounded px-2 py-1 text-[11px] font-medium tabular-nums transition-colors ${
+              preset === p ? 'bg-white/10 text-blue-300' : 'text-gray-500 hover:text-gray-300'
+            }`}
+          >
+            {p}
+          </button>
+        ))}
+        <span className="ml-1 text-[10px] text-gray-600">scroll to zoom · drag to pan</span>
+      </div>
+      <div ref={containerRef} className="relative w-full" style={{ height: 400 }}>
+        <canvas
+          ref={canvasRef}
+          className="w-full"
+          style={{ height: 400 }}
+        />
       <canvas
         ref={overlayCanvasRef}
         className="absolute top-0 left-0 w-full cursor-crosshair"
@@ -643,11 +686,12 @@ export function CandlestickChart({ data, srLevels = [], zones = [], tradeSetup,
         onMouseLeave={handleMouseLeave}
         onWheel={handleWheel}
       />
-      <div
-        ref={tooltipRef}
-        className="glass absolute pointer-events-none px-3 py-2 text-xs shadow-2xl z-50"
-        style={{ display: 'none' }}
-      />
+        <div
+          ref={tooltipRef}
+          className="glass absolute pointer-events-none px-3 py-2 text-xs shadow-2xl z-50"
+          style={{ display: 'none' }}
+        />
+      </div>
     </div>
   );
 }