fix(multicall): resolve critical multicall parsing corruption issues

- Added comprehensive bounds checking to prevent buffer overruns in multicall parsing
- Implemented graduated validation system (Strict/Moderate/Permissive) to reduce false positives
- Added LRU caching system for address validation with 10-minute TTL
- Enhanced ABI decoder with missing Universal Router and Arbitrum-specific DEX signatures
- Fixed duplicate function declarations and import conflicts across multiple files
- Added error recovery mechanisms with multiple fallback strategies
- Updated tests to handle new validation behavior for suspicious addresses
- Fixed parser test expectations for improved validation system
- Applied gofmt formatting fixes to ensure code style compliance
- Fixed mutex copying issues in monitoring package by introducing MetricsSnapshot
- Resolved critical security vulnerabilities in heuristic address extraction
- Progress: Updated TODO audit from 10% to 35% complete

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/8_reports/enhancements/simulation_tools_plan.md

@@ -0,0 +1,33 @@
+# Simulation Tools Enhancement Plan
+
+## Goal
+Align the profitability replay harness and embedded simulation helpers with production requirements: real historical data, accurate fee/slippage modelling, and automated validation in CI.
+
+## Tasks
+
+1. **Historical Data Ingestion**
+   - [ ] Define vector schema for real opportunities (timestamp, DEX, expected vs. realized profit, route data).
+   - [ ] Build extraction pipeline from historical archive/DB to `tools/simulation/vectors/` (with sanitised examples).
+   - [ ] Add versioning/checksums for vectors used in CI.
+
+2. **Simulation Accuracy**
+   - [ ] Replace hard-coded fees/reserves (`tools/simulation/main.go`) with per-exchange metadata.
+   - [ ] Model slippage, gas costs, and failed trades using observed distributions.
+   - [ ] Introduce configuration for latency, backrunning competition, gas spikes.
+
+3. **Integration with Arbitrage Pipeline**
+   - [ ] Provide CLI option to replay directly against `ArbitrageService` / executor in dry-run mode.
+   - [ ] Emit metrics for hit rate and net profit and compare against Prometheus data.
+
+4. **CI Automation**
+   - [ ] Add `make simulate-profit` to staging/audit workflows with artifact retention.
+   - [ ] Set thresholds (e.g., net profit >0, hit rate >50%) to fail CI when regressions occur.
+
+5. **Documentation & Runbooks**
+   - [ ] Update `docs/5_development/TESTING_BENCHMARKING.md` and `docs/6_operations/DEPLOYMENT_GUIDE.md` with guidance on capturing vectors and interpreting reports.
+   - [ ] Provide runbook entry for simulation dashboards and alerting.
+
+## References
+- `tools/simulation/main.go`
+- `scripts/run_profit_simulation.sh`
+- `pkg/arbitrage` simulation helper functions