* docs(browser): document local startup timeout bounds
The new browser.localLaunchTimeoutMs and browser.localCdpReadyTimeoutMs
options are clamped to MAX_BROWSER_STARTUP_TIMEOUT_MS (120000 ms) by
normalizeStartupTimeoutMs in extensions/browser/src/browser/config.ts,
and zero/negative/non-finite values fall back to the defaults. Without
this in the configuration reference, users setting a higher value see
no error and silently get the 120 s ceiling, or set 0 expecting 'no
timeout' and silently get the default.
* docs(browser): clarify startup timeout validation
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Co-authored-by: Peter Steinberger <steipete@gmail.com>