Stop swallowing CancellationException in suspend code

[nathanfallet]

Summary

Several broad catch (e: Exception) blocks and runCatching {} calls in suspend functions were absorbing CancellationException. In Kotlin CancellationException is an Exception (and runCatching catches Throwable), so these blocks silently swallowed it and broke cooperative cancellation.

Why it matters: when the enclosing scope is cancelled (browser.stop() → coroutineScope.cancel(), or a caller's withTimeout), the affected coroutines kept issuing CDP work / completed "successfully" instead of unwinding, and the WebSocket receive loop printed a spurious stack trace on every clean shutdown — classic "won't die" / noisy-shutdown symptoms.

Changes

Each affected site now rethrows CancellationException before the broad catch:

• DefaultConnection.prepareHeadless / prepareExpert — runCatching {} converted to explicit try/catch
• DefaultConnection.startListening — inner (emit) and outer (incoming loop) catches
• DefaultTab.findElementsByText — resolveNode and element-build catches
• DefaultBrowser.testConnection
• DefaultElement.mouseMoveWithTrajectory viewport query

Non-cancellation behavior is preserved (other exceptions remain swallowed/logged exactly as before). Sites that already rethrow (querySelector/querySelectorAll, mouseClick cleanup) were left unchanged to keep the change scoped to the root cause.

Verification (red → green)

Added CancellationPropagationTest, which drives the real findElementsByText via a DefaultTab subclass with a stubbed callCommand (no browser):

• RED (before fix): DOM.resolveNode throws CancellationException, which is swallowed; findElementsByText returns normally → assertFailsWith<CancellationException> fails.
• GREEN (after fix): the cancellation propagates → test passes.

Full :core:jvmTest (real headless Chrome) and :opentelemetry:jvmTest pass with no regressions.

Test plan

• ./gradlew :core:jvmTest --tests "*.CancellationPropagationTest" — red on unfixed code, green after fix
• ./gradlew :core:jvmTest (real Chrome) — all pass
• ./gradlew :opentelemetry:jvmTest — all pass

[codecov]

Codecov Report

❌ Patch coverage is 54.16667% with 11 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...n/dev/kdriver/core/connection/DefaultConnection.kt	54.16%	10 Missing and 1 partial ⚠️

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