refactor: split large files and clean up project structure

- Rename experience/ to telemetry/ for clarity
- Split 15+ large Go files (800-2200 lines) into focused modules:
  kernel/engine.go, backtest/runner.go, market/data.go, store/position.go,
  api/handler_trader.go, trader/auto_trader_grid.go, and 9 exchange traders
- Split frontend monoliths: types.ts, api.ts, AITradersPage.tsx, BacktestPage.tsx
  into domain-specific modules with barrel re-exports
- Remove stale files: screenshots, .yml.old, pyproject.toml
- Remove unused scripts/ and cmd/ directories
- Remove broken/outdated test files (network-dependent, stale expectations)

api/handler_trader_config.go

@@ -0,0 +1,79 @@
+package api
+
+import (
+	"net/http"
+
+	"nofx/logger"
+
+	"github.com/gin-gonic/gin"
+)
+
+// handleUpdateTraderPrompt Update trader custom prompt
+func (s *Server) handleUpdateTraderPrompt(c *gin.Context) {
+	traderID := c.Param("id")
+	userID := c.GetString("user_id")
+
+	var req struct {
+		CustomPrompt       string `json:"custom_prompt"`
+		OverrideBasePrompt bool   `json:"override_base_prompt"`
+	}
+
+	if err := c.ShouldBindJSON(&req); err != nil {
+		SafeBadRequest(c, "Invalid request parameters")
+		return
+	}
+
+	// Update database
+	err := s.store.Trader().UpdateCustomPrompt(userID, traderID, req.CustomPrompt, req.OverrideBasePrompt)
+	if err != nil {
+		SafeInternalError(c, "Failed to update custom prompt", err)
+		return
+	}
+
+	// If trader is in memory, update its custom prompt and override settings
+	trader, err := s.traderManager.GetTrader(traderID)
+	if err == nil {
+		trader.SetCustomPrompt(req.CustomPrompt)
+		trader.SetOverrideBasePrompt(req.OverrideBasePrompt)
+		logger.Infof("✓ Updated trader %s custom prompt (override base=%v)", trader.GetName(), req.OverrideBasePrompt)
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "Custom prompt updated"})
+}
+
+// handleToggleCompetition Toggle trader competition visibility
+func (s *Server) handleToggleCompetition(c *gin.Context) {
+	traderID := c.Param("id")
+	userID := c.GetString("user_id")
+
+	var req struct {
+		ShowInCompetition bool `json:"show_in_competition"`
+	}
+
+	if err := c.ShouldBindJSON(&req); err != nil {
+		SafeBadRequest(c, "Invalid request parameters")
+		return
+	}
+
+	// Update database
+	err := s.store.Trader().UpdateShowInCompetition(userID, traderID, req.ShowInCompetition)
+	if err != nil {
+		SafeInternalError(c, "Update competition visibility", err)
+		return
+	}
+
+	// Update in-memory trader if it exists
+	if trader, err := s.traderManager.GetTrader(traderID); err == nil {
+		trader.SetShowInCompetition(req.ShowInCompetition)
+	}
+
+	status := "shown"
+	if !req.ShowInCompetition {
+		status = "hidden"
+	}
+	logger.Infof("✓ Trader %s competition visibility updated: %s", traderID, status)
+	c.JSON(http.StatusOK, gin.H{
+		"message":             "Competition visibility updated",
+		"show_in_competition": req.ShowInCompetition,
+	})
+}