Update compute worker to use separate environment variable for PDF job attempts
(`COMPUTE_PDF_JOB_ATTEMPTS`) and set Whisper job max deliveries to 1, clarifying
and separating retry logic between job types. Adjust `.env.example` and deployment
docs to comment out defaults and document new/renamed variables for advanced tuning.
In TTS segment ensure route, introduce explicit timeouts for Whisper alignment
operations, with configurable durations for local and worker modes, improving
robustness and error handling for long-running alignments.