Sync: Fix renderer crash when network disconnects after upload

[gavande1]

Related issues

• Fixes STU-1180

Proposed Changes

• Added error handling in getPushProgressInfo to catch network errors gracefully
• Skip Sentry reporting for expected crossDomain network errors (offline scenarios)
• Prevent unhandled promise rejections when network goes offline

Testing Instructions

1. Start a new sync operation
2. Allow the upload step to complete successfully
3. Disconnect the network (e.g., turn off Wi‑Fi) during subsequent sync steps
4. Verify the renderer no longer crashes and handles the offline state gracefully
5. Verify that when the network reconnects, the sync operation can continue

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[github-actions]

📊 Performance Test Results

Comparing 3c6b618 vs trunk

site-editor

Metric	trunk	3c6b618	Diff	Change
load	17618.00 ms	15133.00 ms	-2485.00 ms	🟢 -14.1%

site-startup

Metric	trunk	3c6b618	Diff	Change
siteCreation	30196.00 ms	29002.00 ms	-1194.00 ms	🟢 -4.0%
siteStartup	11070.00 ms	12050.00 ms	+980.00 ms	🔴 8.9%

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Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change