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/start_backtesting.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+# Load environment variables
+set -a
+source /home/jgrusewski/Work/foxhunt/.env
+set +a
+
+# Set backtesting-specific variables
+export GRPC_PORT=50052
+export ENVIRONMENT=production
+export MODEL_CACHE_DIR=/tmp/foxhunt/model_cache
+export ENABLE_HTTP2_OPTIMIZATIONS=true
+
+# Create model cache directory
+mkdir -p ${MODEL_CACHE_DIR}
+
+# Start backtesting service
+cd /home/jgrusewski/Work/foxhunt
+exec ./target/release/backtesting_service