fix(packaged): swallow EPIPE in console echo to stop main-process crash - #7446

Closes nexu-io#6964.

Packaged Electron builds on Windows / Linux have no controlling
terminal, so process.stdout / process.stderr are typically detached
or piped to a closed handle. The first console.info(...) a renderer
lifecycle handler fires (e.g. webContents 'did-start-loading')
raises 'Error: EPIPE: broken pipe, write' from
node:internal/streams/writable.

Because the throw happens inside Writable.write (not at the call
site), the existing console.* echo wrapper installed by
createPackagedDesktopLogger lets the error escape into the uncaught
exception path, surfacing as Electron's native 'JavaScript error in
main process' dialog and crashing the app.

Wrap each echo in a safeEcho helper that catches only the two
known-safe stream-closure codes (EPIPE, ERR_STREAM_DESTROYED);
anything else is re-thrown so real I/O failures are not silently
dropped. The structured file logger (which already swallows its own
append failures) is unaffected.

Tests: add isHarmlessStdoutError matcher coverage and two regression
tests that exercise the wrapper with simulated EPIPE / EACCES echo
failures. The narrow-match philosophy mirrors the existing
isHarmlessSocketOptionError helper for issue nexu-io#895 so a future
broadening of the filter trips a test.

The first revision of the wrapper tests stubbed console.info AFTER
constructing the logger, which meant the bare throwing stub was
hit directly and safeEcho was never exercised. Per PR nexu-io#6965 review
from mrcfps, both tests now stub the host console BEFORE the
factory so originalConsole.{info,error} captures the throwing
original, and assertions read from the real desktop log file
(logger.info is a plain function, not a vi.fn()). Both tests
verified end-to-end against the compiled createPackagedDesktopLogger
in a standalone harness.