feat(web): v1.4.0 UI — backtest results, trade stats, dot grid background

backtest page:
- equity progression SVG chart ($5k → $27,439)
- filter impact cards (ATR gate, entry zone 75%, session)
- v1.4.0 results: PF 2.08, +448.7%, WR 62.7%

trades page:
- avg win/loss, friction, streak tiles
- win/loss distribution bar (visual green/red)
- best trade + worst trade highlight cards

home page:
- 4 strategy cards (added ATR Quality Gate)
- backtest CTA updated to v1.4.0 numbers with v1.3.0 comparison

globals/layout:
- dot grid background pattern
- top accent glow (purple radial)
- edge vignette fade

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/app/globals.css

@@ -29,6 +29,28 @@ html, body {
   -webkit-font-smoothing: antialiased;
 }
 
+/* ── Background texture ──────────────────────────────────────────────────── */
+body {
+  background-image:
+    /* top accent glow */
+    radial-gradient(ellipse 70% 40% at 50% -5%, rgba(94,106,210,0.10) 0%, transparent 70%),
+    /* dot grid */
+    radial-gradient(circle, rgba(255,255,255,0.045) 1px, transparent 1px);
+  background-size: auto, 28px 28px;
+  background-attachment: fixed;
+}
+
+/* subtle side vignette so grid fades at edges */
+body::after {
+  content: '';
+  position: fixed;
+  inset: 0;
+  pointer-events: none;
+  z-index: 0;
+  background:
+    radial-gradient(ellipse 100% 100% at 50% 50%, transparent 60%, var(--c-canvas) 100%);
+}
+
 /* ── Buttons ─────────────────────────────────────────────────────────────── */
 .btn-primary {
   display: inline-flex; align-items: center; gap: 8px;