Function markPerformance

markPerformance(name: string): void
Mark a performance timing point

Creates a named performance mark for custom timing measurements.
Parameters
- name: string
  Name of the performance mark
Returns void
Example
```
markPerformance('component-start');
// ... component initialization
markPerformance('component-end');
const duration = measurePerformance('component-init', 'component-start', 'component-end');
```
- Defined in performance/metrics.ts:215