Added `ignoreErrors` to the Sentry `init()` configuration in `SentryInitEffect.tsx` to filter out transient browser network errors that are not actionable:
- `NetworkError when attempting to fetch resource` — Firefox's TypeError for failed fetch
- `Failed to fetch` — Chrome/Edge's TypeError for failed fetch
- `Load failed` — Safari's TypeError for failed fetch
These errors occur when the browser loses connection to the server (e.g., during a transient 502 from Cloudflare). They are not bugs — they are symptoms of transient infrastructure availability that self-resolve. Capturing them in Sentry creates noise without actionable signal.