navigateChromeMcpPage() now always passes a timeout to the Chrome MCP
navigate_page tool (defaulting to CHROME_MCP_NAVIGATE_TIMEOUT_MS when
the caller omits timeoutMs), and callTool() grows an optional safety-net
that tears down a stuck session via Promise.race so the next caller gets
a fresh subprocess. The catch block gains a transport-identity guard to
avoid clobbering a concurrently-created replacement session.