fix(lens): prevent crashes when closing tabs

[heath-s]

Summary

• detach the native Lens view before teardown and retain its wrapper until WebContents destruction completes
• tombstone closing sessions, reject stale event/CDP work, and force-detach stalled diagnostics
• bound guest console payloads and event rates, automatically stopping full diagnostics under sustained overload
• synchronize automatic diagnostics shutdown with the renderer without allowing stale async responses to re-enable the UI

Root cause

Local macOS crash reports showed both a WebContents lifecycle weak-callback failure during tab teardown and an out-of-memory path while handling page console messages. Closing a Lens tab could leave the native surface visible while stale listeners or CDP work continued, and high-volume console events were cloned and re-logged without byte or rate bounds.

Impact

Closing Lens tabs now removes the native surface immediately, prevents late session traffic from reaching replacement tabs, and keeps console/CDP overload from taking down Stave.

Verification

• bun run test:ci
• Lens regression suite: 190 tests passed
• independent High/Medium review completed with no remaining findings

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Apply the popup cap only to URLs that create popups

When three HTTP(S) auth windows are already open, this early limit check also rejects mailto:, custom-protocol, and other external links, even though the branch below would send those URLs to openExternalWithFallback without creating another popup. Move the non-HTTP(S) handling before the auth-popup count check so ordinary external links continue working at the popup limit.

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