Contributing Guide

cargo install tombi

## Description
Brief description of what this PR does.

## Related Issue
Closes #123

## Changes
- List key changes
- Made in this PR

## Testing
Describe how you tested the changes:
- Ran unit tests
- Tested in playground
- Manual testing steps

## Checklist
- [ ] Tests added/updated
- [ ] Documentation updated (if needed)
- [ ] Formatted with `just fmt` and `just fmt-toml`
- [ ] Clippy passes

brief summary of change (50 chars or less)

More detailed explanation if needed. Explain WHY you made the change,
not just WHAT changed. The code shows what changed.

- Can use bullet points
- To list multiple aspects

References #123

Fix race condition in orderbook insertion

Orders could be inserted with outdated validation state if another
order was processed concurrently. Added proper locking around the
validation + insertion sequence.

Fixes #456

Add support for ERC-1271 signature validation

Enables smart contract wallets to place orders by implementing
ERC-1271 signature verification. Required for CoW Swap smart
wallet support.

References #789

fixed bug  ❌  (too vague)

Updated orderbook.rs  ❌  (doesn't explain why)

refactor  ❌  (no details)

// External crates
use anyhow::Result;
use tokio::sync::Mutex;

// Internal crates
use crate::database::Db;
use crate::orderbook::Order;

// Local modules
use super::validation;

// Good ✓
use shared::arguments::TokenBucketFeeOverride;

fn process(overrides: Vec<TokenBucketFeeOverride>) {
    // ...
}

// Bad ✗
fn process(overrides: Vec<shared::arguments::TokenBucketFeeOverride>) {
    // ...
}

// Bad ✗
// Increment counter
counter += 1;

// Good ✓
// We need to delay here to avoid overwhelming the RPC node with requests.
// The rate limit is 10 requests per second.
tokio::time::sleep(Duration::from_millis(100)).await;

use anyhow::{Context, Result};

fn process_order(order: Order) -> Result<()> {
    validate_order(&order)
        .context("failed to validate order")?;
    
    store_order(&order)
        .context("failed to store order")?;
    
    Ok(())
}

# 1. Format code
just fmt
just fmt-toml

# 2. Lint
just clippy

# 3. Test
just test-unit
docker compose up -d && just test-db

# 4. Verify formatting
just fmt --check
just fmt-toml --check