🐛 Align session-ended WebSocket teardown with the latest view's end clocks

[bdibon]

Motivation

When a RUM session expires, open WebSocket connections are finalized with tracking_end_reason: 'session_end'. Until now the teardown used clocksNow() as the end time. Because the active view is ended before the SDK reaches the session-boundary cleanup, clocksNow() lands slightly after the view's end_time — so the resulting websocket-closed vital was dropped during assembly and the resource's end_time fell outside the lifespan of the view it was attached to.

Changes

• Add ViewHistory.getLatestViewEndClocks(), returning the end clocks of the most recently ended view (reset on SESSION_RENEWED), documented with its intended session-boundary use.
• On SESSION_EXPIRED, thread those end clocks into flushOpenConnections so the websocket-closed vital startClocks, the resource end_time, and end_view_id all stay within the ending view's window. flushOpenConnections still falls back to clocksNow() when no end clocks are available (e.g. the collection's own stop()).
• Unit tests for the new getter (set / boundary / reset-on-renew) and the wired session-end path.
• E2E test asserting the websocket-closed vital and resource end_time do not exceed the associated view's end time.

Ordering note: this relies on trackViews' SESSION_EXPIRED subscriber (registered first) ending the view and notifying AFTER_VIEW_ENDED synchronously before webSocketCollection's subscriber reads getLatestViewEndClocks().

Test instructions

yarn test:unit --spec packages/browser-rum-core/src/domain/contexts/viewHistory.spec.ts
yarn test:unit --spec packages/browser-rum-core/src/domain/resource/webSocketCollection.spec.ts
yarn build:apps && yarn test:e2e -g "websocket-closed vital when the session expires"

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated documentation and/or relevant AGENTS.md file

🤖 Generated with Claude Code

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	179.09 KiB	179.16 KiB	+75 B	+0.04%	✅
Rum Profiler	8.43 KiB	8.43 KiB	0 B	0.00%	✅
Rum Recorder	21.12 KiB	21.12 KiB	0 B	0.00%	✅
Logs	55.71 KiB	55.71 KiB	0 B	0.00%	✅
Rum Salesforce	N/A	137.14 KiB	N/A	N/A	N/A
Rum Slim	137.06 KiB	137.13 KiB	+75 B	+0.05%	✅
Worker	22.96 KiB	22.96 KiB	0 B	0.00%	✅

[datadog-datadog-prod-us1]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 77.23% (+0.01%)

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