[v2] unhandledrejection bridge brands all page rejections as "QWIK ERROR"

Which component is affected?

Qwik Runtime (v2 / build/v2) — client error handling, added by the ErrorBoundary PR #8745.

Describe the bug

The window-level bridge in packages/qwik/src/core/client/dom-container.ts:146 registers addEventListener('unhandledrejection', (e) => logError(e?.reason)) with no Qwik-origin filter, so it fires for every unhandled promise rejection on the page — including rejections from third-party scripts or app code unrelated to Qwik. Because logError (shared/utils/log.ts) prefixes %cQWIK ERROR in Qwik's style, a foreign rejection gets misattributed to Qwik.

What is already fine (verified, not part of this issue): per-window dedup works (one listener per view via a WeakSet; a spec pins exactly-one registration across two containers), and there is no double-log with a boundary-handled error (the boundary path uses logErrorAndThrowAsync → window.onerror, disjoint from unhandledrejection).

Scope / fix direction

The bridge intentionally routes otherwise-lost fire-and-forget rejections to logError/monitoring (an e2e pins this), so the goal is not to stop logging — only to stop branding non-Qwik rejections as Qwik. There is no cheap reliable filter today (e.reason is opaque with no Qwik marker), so this needs a small design pass, e.g.:

• a neutral log label for rejections not traceable to a Qwik boundary, or
• tag Qwik-originated rejection reasons so only those get the QWIK ERROR branding.

Also consider (but likely don't): the bridge does not call e.preventDefault(), so a genuine Qwik rejection surfaces twice (native "Uncaught (in promise)" + branded QWIK ERROR). Suppressing the native one would hide the rejection from other tooling (e.g. Sentry's own unhandledrejection handler), so leaving it un-suppressed is probably correct — noted here so it's decided deliberately.

Net-new in #8745; DX-only, does not block that PR.

Start in packages/qwik/src/core/client/dom-container.ts:146 and read the unhandledrejection bridge together with shared/utils/log.ts. Review the existing one-listener spec and the e2e coverage that preserves logging, then decide how Qwik-originated and foreign rejections should be distinguished. Done means non-Qwik rejections are no longer branded QWIK ERROR while Qwik rejection logging and monitoring remain covered.