fix(cli): Ignore SIGPIPE to prevent crashes on broken pipes

[sentry]

This PR addresses an issue where the CLI would crash with a SIGPIPE signal when its stdout was piped to another command that exited early (e.g., apple-docs ... | head -n 1).

The root cause was that the application did not explicitly ignore the SIGPIPE signal. By default, writing to a pipe whose reader has closed results in a SIGPIPE signal, which terminates the process.

The fix involves calling signal(SIGPIPE, SIG_IGN) in AppleDocs.main() to instruct the operating system to ignore this signal. This ensures that writes to a broken pipe will instead fail with an EPIPE error, allowing the CLI to exit gracefully without crashing.

The signal(SIGPIPE, SIG_IGN) call is placed after telemetry.start() to ensure it takes precedence over any SIGPIPE handler that Sentry's crash reporter might install during its initialization.

Fixes APPLE-DOCS-CLI-3

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