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- Remove broken/outdated test files (network-dependent, stale expectations)

trader/auto_trader_decision.go

@@ -3,7 +3,7 @@ package trader
 import (
 	"fmt"
 	"math"
-	"nofx/experience"
+	"nofx/telemetry"
 	"nofx/kernel"
 	"nofx/logger"
 	"nofx/market"
@@ -345,7 +345,7 @@ func (at *AutoTrader) recordAndConfirmOrder(orderResult map[string]interface{},
 
 	// Send anonymous trade statistics for experience improvement (async, non-blocking)
 	// This helps us understand overall product usage across all deployments
-	experience.TrackTrade(experience.TradeEvent{
+	telemetry.TrackTrade(telemetry.TradeEvent{
 		Exchange:  at.exchange,
 		TradeType: action,
 		Symbol:    symbol,