feat: cream terminal redesign, English-only UI, autopilot launch fixes

- Redesign dashboard into a cream-paper + vermilion IBM Plex Mono terminal
  (live L2 order book, cost/liq map, WS K-line, signal matrix, orchestration
  topology, risk radar, execution log, current positions, equity curve)
- Convert all user-facing UI and backend strings/prompts from Chinese to
  English (multi-language retained, default English)
- Add /api/statistics/full endpoint + full-stats frontend wiring
- Fix Autopilot launch: reuse the existing trader instead of creating
  duplicates (eliminates repeat ~35s create cost and stale-trader 404s);
  launch sends 5m scan interval
- Fix unreadable toasts: cream theme with high-contrast text + per-type accent
- Silence background dashboard polls (getTraderConfig) to stop error-toast spam

trader/auto_trader_force.go

@@ -0,0 +1,99 @@
+package trader
+
+import (
+	"strings"
+
+	"nofx/kernel"
+)
+
+// ensureLongShortCoverage keeps a balanced book each cycle: it fills toward
+// roughly half the MaxPositions slots long and half short. The AI still drives
+// selection/sizing whenever it acts; this is a deterministic top-up — if the
+// AI's decisions plus existing positions fall short of the per-direction target,
+// the engine force-opens the strongest unused bullish/bearish candidates to
+// reach it (never exceeding MaxPositions).
+//
+// Forced opens are sized from account equity via applyAutopilotFullSizeOpen and
+// run through the same code-enforced risk checks (position-value ratio, minimum
+// size, margin) as any other open. Guards:
+//   - skipped entirely in safe mode (AI unhealthy),
+//   - scoped to the vergex_signal source (the only one with directional bias),
+//   - never exceeds MaxPositions,
+//   - never doubles a base symbol already held or already in the decision set.
+func (at *AutoTrader) ensureLongShortCoverage(decisions []kernel.Decision, ctx *kernel.Context, equity float64) []kernel.Decision {
+	if at == nil || ctx == nil || at.safeMode {
+		return decisions
+	}
+	if at.config.StrategyConfig == nil || at.config.StrategyConfig.CoinSource.SourceType != "vergex_signal" {
+		return decisions
+	}
+	if at.strategyEngine == nil || equity <= 0 {
+		return decisions
+	}
+
+	maxPos := at.config.StrategyConfig.RiskControl.MaxPositions
+	if maxPos < 2 {
+		return decisions
+	}
+	// Aim to hold a balanced book: roughly half the slots long, half short.
+	targetLong := (maxPos + 1) / 2
+	targetShort := maxPos / 2
+
+	held := make(map[string]bool)
+	longCount, shortCount, posCount := 0, 0, 0
+	for _, p := range ctx.Positions {
+		held[universeBaseKey(p.Symbol)] = true
+		posCount++
+		if strings.EqualFold(p.Side, "long") {
+			longCount++
+		} else if strings.EqualFold(p.Side, "short") {
+			shortCount++
+		}
+	}
+	for _, d := range decisions {
+		held[universeBaseKey(d.Symbol)] = true
+		switch d.Action {
+		case "open_long":
+			longCount++
+			posCount++
+		case "open_short":
+			shortCount++
+			posCount++
+		}
+	}
+
+	bullish, bearish := at.strategyEngine.DirectionalCandidates()
+
+	// fill a direction up to its target, drawing from the strongest unused
+	// candidates, never exceeding MaxPositions.
+	fill := func(action string, cands []string, have, target int) {
+		for _, c := range cands {
+			if have >= target {
+				return
+			}
+			if maxPos > 0 && posCount >= maxPos {
+				return
+			}
+			b := universeBaseKey(c)
+			if b == "" || held[b] {
+				continue
+			}
+			d := kernel.Decision{
+				Action:     action,
+				Symbol:     c,
+				Confidence: 70,
+				Reasoning:  "Forced " + action + " to fill the balanced long/short book (autopilot)",
+			}
+			at.applyAutopilotFullSizeOpen(&d, equity)
+			decisions = append(decisions, d)
+			held[b] = true
+			have++
+			posCount++
+			at.logInfof("⚖️ Forced %s %s (account-sized %.2f USDT, %dx)", action, c, d.PositionSizeUSD, d.Leverage)
+		}
+	}
+
+	fill("open_long", bullish, longCount, targetLong)
+	fill("open_short", bearish, shortCount, targetShort)
+	return decisions
+}