[Due for payment 2026-07-21] fix: drop canceled tab navigation spans and add Inbox span context attributes

[mountiny]

Problem

The tab-navigation spans (ManualNavigateToInboxTab, ManualNavigateToReports*) contain events that don't measure a navigation. Abandoned navigations are canceled but still sent with status OK and wall-clock durations, so a span canceled after the laptop wakes up records the whole absence — up to 2-hour "navigations" in production. Under 1% of web events but 61% of recorded time (web avg 1250ms with them, ~420ms without). Wide vs narrow layouts (~3x cost difference) and warm re-focuses (~30ms) vs cold mounts (~150ms) were also indistinguishable in the data.

Solution

Added canceledTabNavigationFilter in beforeSend to drop canceled tab-navigation spans (only matches tab-navigation ops with the canceled attribute set by cancelSpan). Added new Inbox span attributes for honest slicing: wide_layout, skeleton_shown, and is_warm. Removed dead render-duration instrumentation from useSidebarOrderedReports.

PR

#95480

Issue Owner

Current Issue Owner: @marufsharifi