chore: Second cleanup wave - organize root directory

- Archive: 85 agent .txt files → docs/archive/agents/legacy_txt/
- Scripts: Move 110 shell scripts → scripts/ (keep deploy.sh in root)
- Models: Move 18 .safetensors → ml/models/checkpoints/training_artifacts/
- Delete: 34 directories (~33GB freed) - target/, coverage_*, test artifacts
- Build: Clean 14 build artifacts (.rlib, .o, .pid, binaries)
- Tests: Move 14 .rs files → tests/standalone/
- SQL: Move 5 files → sql/ (keep init-db*.sql for Docker)
- Wave 153: Archive to docs/archive/historical/wave153/
- Docs: Archive 9 markdown files to wave_d/reports/ and historical/

Total impact: ~34GB freed (both waves), root directory cleaned from 583 to ~40 essential files
Directory count reduced from 65 to 31 (52% reduction)
All historical data preserved in organized archive structure

scripts/validate_ab_testing_tdd.sh

@@ -0,0 +1,61 @@
+#!/bin/bash
+# Validation Script for A/B Testing Pipeline TDD Implementation
+# This script validates the TDD implementation by running tests and checking compilation
+
+set -e
+
+echo "============================================"
+echo "A/B Testing Pipeline TDD Validation"
+echo "============================================"
+echo ""
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+echo "Step 1: Check Docker services"
+echo "--------------------------------------------"
+docker-compose ps postgres redis
+echo ""
+
+echo "Step 2: Run database migrations"
+echo "--------------------------------------------"
+cargo sqlx migrate run || {
+    echo -e "${RED}Migration failed. Check migration syntax.${NC}"
+    exit 1
+}
+echo -e "${GREEN}Migrations completed successfully${NC}"
+echo ""
+
+echo "Step 3: Compile trading_service"
+echo "--------------------------------------------"
+cargo check -p trading_service --tests 2>&1 | tail -20
+echo -e "${GREEN}Compilation check complete${NC}"
+echo ""
+
+echo "Step 4: Run A/B testing pipeline tests"
+echo "--------------------------------------------"
+echo -e "${YELLOW}Expected: Tests should FAIL (TDD RED phase)${NC}"
+echo ""
+
+cargo test -p trading_service --test ab_testing_pipeline_tests --no-fail-fast 2>&1 | tee ab_testing_test_results.log
+
+echo ""
+echo "============================================"
+echo "Validation Complete"
+echo "============================================"
+echo ""
+echo "Test Results Summary:"
+echo "--------------------------------------------"
+grep -E "(test result:|running)" ab_testing_test_results.log | tail -5
+echo ""
+echo "Full test output saved to: ab_testing_test_results.log"
+echo ""
+echo "Next Steps (TDD Cycle):"
+echo "1. Review test failures (expected in RED phase)"
+echo "2. Fix compilation errors if any"
+echo "3. Fix implementation to make tests pass (GREEN phase)"
+echo "4. Refactor and optimize (REFACTOR phase)"
+echo "5. Integrate with ensemble coordinator"