* fix(browser): use openTab return value to prevent wsUrl race in ensureTabAvailable
When ensureTabAvailable opens a new tab on empty list, the return value
from openTab was discarded. A subsequent listTabs() call may return tabs
without webSocketDebuggerUrl populated yet, causing the wsUrl filter to
eliminate the newly opened tab and throw BrowserTabNotFoundError.
Fix: capture openTab's return value and merge it into candidates if the
wsUrl filter excluded it. openTab's internal discovery loop already
resolves wsUrl, so the returned tab is always valid.
* fix(browser): harden tab selection discovery
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Co-authored-by: Vincent Koc <vincentkoc@ieee.org>
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