fix(studio): suppress ResizeObserver loop noise from error telemetry

[miguel-heygen]

Summary

• Suppress ResizeObserver loop completed with undelivered notifications. errors in the Studio global error handler — this is a benign browser-internal message (not a real bug) that was flooding telemetry with ~18,000 events/month, drowning out actionable errors.
• The guard checks event.message for "ResizeObserver loop" at the top of the window.addEventListener("error", ...) handler and short-circuits with stopImmediatePropagation() + preventDefault() before reaching trackStudioEvent.

Test plan

• Open Studio in Chrome/Firefox, resize panels and timeline to trigger ResizeObserver recalculations — verify no unhandled_error telemetry events are emitted for ResizeObserver loop messages.
• Trigger a real JS error (e.g., via console throw new Error("test")) — verify it still appears in telemetry as unhandled_error.
• Confirm the browser console no longer shows the ResizeObserver warning (prevented by preventDefault()).

[jrusso1020]

Verdict: COMMENT (would-be APPROVE)

Tiny well-scoped fix using the canonical ResizeObserver loop suppression pattern (event.message.includes(...) + stopImmediatePropagation() + preventDefault() at the top of the global error handler). 6 lines, one file. Holding for James's stamp greenlight.

Sanity checks

• Scope is correct — studio window only, not preview iframe. The PostHog unhandled_error event originates from packages/studio/src/main.tsx:25 (the studio window's error listener); the preview iframe's errors flow through useConsoleErrorCapture.ts:37-44 into consoleErrors state for the UI's error console, not into telemetry. So suppressing studio-window ResizeObserver noise is sufficient — there's no secondary pipeline still ingesting it.
• Source of the 18k events/month confirmed plausible. Studio uses ResizeObserver at NLEPreview.tsx:137 (preview stage sizing) and AudioWaveform.tsx:141 (waveform redraw). Both run on user resize / panel adjustment, which fires often.
• Browser coverage: substring "ResizeObserver loop" matches Chrome's "ResizeObserver loop completed with undelivered notifications." AND Firefox's "ResizeObserver loop limit exceeded". ✓
• Convention consistency: matches the existing benign-error filter pattern at useConsoleErrorCapture.ts:30 (if (text.includes("favicon")) return;).
• CI: 23 success / 2 in_progress / 0 failures.

One optional follow-up

The unhandledrejection listener (main.tsx:35) doesn't have a matching guard. In practice, ResizeObserver loop notifications fire as window-error events, not as promise rejections — so this isn't a real source of leakage. But if anyone wraps ResizeObserver in a promise abstraction in the future (or if a library does so under the hood), the noise would resurface there. Optional defense-in-depth: add the same if (...includes("ResizeObserver loop")) return; guard to the rejection listener too. Not blocking; the current fix solves the actual problem.

— Rames Jusso