Fix potential error when worker process crashes

[gaborcsardi]

Reading the output might fail, so we need to tryCatch() it.

Closes #2262.

[claude]

Claude finished @gaborcsardi's task —— View job

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Code Review Progress

• Read and analyze the changed file
• Review tryCatch implementation
• Provide feedback on potential issues

Review Findings

The changes wrap four worker process output reading calls with a safely() function to handle potential errors when reading from crashed worker processes.

Issue identified: Line 96 in the inc assignment calls safely(worker$read_output(), "") but line 100 uses nchar(inc) without checking if inc is NULL. If both worker$read_output() and worker$read_error() fail, inc could be "" + "" = "", which is fine. However, the logic assumes paste0() always returns a character, which it should.

Minor concern: The safely() function doesn't log or track that errors occurred during output reading, which might make debugging worker crashes more difficult.

Otherwise the fix looks appropriate for handling crashed worker processes gracefully.