## Silent setTimeout / Async Callback Errors

### Session Context

Debugged in ShopProQuote (PocketBase web app) — "Mark as Completed" flow on repair orders.

### The Bug

Clicking work-status-badge → "Completed" → confirm modal → nothing. Financial summary modal never appeared. No console errors.

### The Chain

1. User clicks confirm button in dynamically-created confirm modal element
2. Click handler calls `updateRepairOrderWorkStatus(roId, 'completed')` (async)
3. Inside, code reaches `if (newWorkStatus === 'completed')` branch (confirmed by console.log)
4. `setTimeout(() => { openFinancialSummaryModal(roId); }, 100)` is scheduled
5. `return` exits both the function and the enclosing `try/catch`
6. 100ms later, `openFinancialSummaryModal` runs — this is NOW outside any try/catch
7. Line 1545: `document.getElementById('financial-customer-name').textContent = ...`
8. `#financial-customer-name` never existed in the HTML → `null.textContent` → `TypeError`
9. The TypeError is uncaught (no try/catch in the detached context) → global error handler
10. Global error handler does nothing visible → user sees "nothing happens"

### The Tool That Caught It

Overriding `window.setTimeout` from Playwright:

```python
page.evaluate("""()=>{
    window.__origSetTimeout = window.setTimeout.bind(window);
    window.setTimeout = function(fn, delay) {
        if(delay===100) {
            return window.__origSetTimeout(function(){
                try { return fn(); }
                catch(e) { console.error('TIMEOUT ERROR:', e); }
            }, delay);
        }
        return window.__origSetTimeout(fn, delay);
    };
}""")
```

This logged: `TIMEOUT ERROR: TypeError: Cannot set properties of null (setting 'textContent') at openFinancialSummaryModal (repair-orders.js:1545:72)`

### The Fix

Added missing `<span id="financial-customer-name">--</span>` to the `financial-summary-modal` HTML in `repair-orders.html`.

### Verification Pattern

After the fix, the full keyboard+click flow was re-tested end-to-end via Playwright:
1. Create repair order (fill form)
2. Click work status badge → select "Completed"
3. Confirm modal → financial modal appears
4. Fill CP Total / CP Cost
5. Click "Complete" → modal closes, notification shows

One way to `overwrite for robust test runs`:
```python
# Trap ALL setTimeout errors during test
page.evaluate("""()=>{
    const _st=window.setTimeout.bind(window);
    window.setTimeout=(fn,d)=>_st(function(){
        try{return fn()}catch(e){console.error('setTimeout ERROR:',e.stack||e)}
    },d);
}""")
```