feat: autonomous trading toolkit — risk guardrails, PnL tracking, strategy runner

[dolepee]

Summary

Complete agent-first trading toolkit for autonomous Clawlett agents, built on top of the CoW Protocol swap engine. All features integrate cleanly with the new CoW presign/batch/fill flow.

• Risk guardrails on swap.js: max balance usage cap per trade + ETH reserve protection
• JSON output mode on swap.js: --json flag for machine-readable quote/execute responses (includes orderUid, CoW explorer links)
• Trade history logger: automatic PnL tracking per swap with CoW order UIDs, CSV export, reset
• Strategy runner: DCA, limit order, and rebalance strategies with proper CoW async order handling
• README: updated for CoW Protocol — contracts, env vars, examples

What's included

File	Change	Lines
swap.js	Risk guards + JSON mode + auto trade logging	+219/-62
strategy.js	New: DCA, limit, rebalance strategy runner	+457
trade-history.js	New: PnL tracker with JSON/CSV export	+227
README.md	Updated for CoW Protocol + new feature docs	+103

Risk Guardrails (swap.js)

# Cap each trade to 10% of balance
node swap.js --from ETH --to USDC --amount 5 --max-balance-usage-pct 10 --execute

# Keep ETH reserve for gas (accounts for WETH wrapping)
node swap.js --from ETH --to USDC --amount 0.5 --min-safe-eth-reserve 0.01 --execute

Configurable via env (MAX_BALANCE_USAGE_PCT, MIN_SAFE_ETH_RESERVE) or CLI flags.

JSON Output (swap.js)

node swap.js --from ETH --to USDC --amount 0.1 --json
# Returns: { mode, from, to, quote: { amountOut, fee, minReceive, slippagePct, expiresIn } }

node swap.js --from ETH --to USDC --amount 0.1 --json --execute
# Returns: { mode, status, orderUid, explorer, from, to, amountOut, newBalance }

Handles all CoW order states: fulfilled, expired, cancelled, timeout.

PnL Tracking (trade-history.js)

Every executed swap is automatically logged with CoW order UIDs. Tracks stablecoin inflows/outflows for realized PnL.

node trade-history.js              # Human-readable PnL summary
node trade-history.js --json       # Machine-readable
node trade-history.js --export trades.csv  # Includes CoW explorer links

Strategy Runner (strategy.js)

All strategies handle CoW's async order lifecycle (presign → batch → fill) with appropriate timeouts (35 min for executions, 60s for quotes).

# DCA into ETH every hour
node strategy.js --strategy dca --from USDC --to ETH --amount 10 --interval 3600

# Rebalance: maintain 60/40 ETH/USDC (reads balances, computes drift, swaps)
node strategy.js --strategy rebalance --tokens ETH,USDC --target 60,40 --threshold 5

# Limit order: sell when price target met
node strategy.js --strategy limit --from ETH --to USDC --amount 0.1 --min-out 280

# Dry run any strategy
node strategy.js --dry-run --strategy dca --from USDC --to AERO --amount 5

The rebalance strategy reads actual Safe balances, gets USDC-denominated prices via CoW quotes, computes portfolio drift against target allocation, and executes the swap if drift exceeds the threshold.

Why

Autonomous agents competing in the Clawlett challenge need:

1. Safety rails to prevent oversized trades and gas starvation
2. Machine-readable output to parse results without brittle log scraping
3. PnL tracking to measure competition performance
4. Strategy primitives (DCA, limit, rebalance) as building blocks for custom logic

Scope

Non-breaking: all existing swap.js behavior preserved. New features are opt-in via flags. README updated to reflect CoW Protocol migration.

Supersedes #2 and #3 (consolidated into this PR).