Enhance pipeline logging

[yoonspark]

Got the following feedback:

• Add a log message for informing completion of all staged files, like so:

  2025-09-22 09:20:10 | INFO     | Starting pipeline execution
  ...
  2025-09-22 09:23:15 | INFO     | Completed processing 6 file(s)
  2025-09-22 09:23:55 | INFO     | Completed processing 1 file(s)
  2025-09-22 09:23:55 | INFO     | No more files to process, staring idle time count
  ...
  2025-09-22 09:33:48 | WARNING  | Idle timeout reached, initiating shutdown
  2025-09-22 09:33:48 | INFO     | Shutting down pipeline
  ...
  2025-09-22 09:33:51 | INFO     | Pipeline shutdown complete
  

• At pipeline termination, log the total number of processed vs. failed files out of all files staged during that run, like so:

  2025-09-22 09:20:10 | INFO     | Starting pipeline execution
  ...
  2025-09-22 09:23:15 | INFO     | Completed processing 6 file(s)
  2025-09-22 09:23:55 | INFO     | Completed processing 1 file(s)
  ...
  2025-09-22 09:33:48 | INFO     | Shutting down pipeline
  ...
  2025-09-22 09:33:51 | INFO     | Pipeline shutdown complete
  2025-09-22 09:33:51 | INFO     | Pipeline summary: staged=59 / completed=56 / failed=3
  

• Periodically log warnings for long-pending workers (for a Slurm task), like so:

  2025-09-22 09:20:10 | INFO     | Starting pipeline execution
  2025-09-22 09:20:10 | INFO     | [transcribe] Starting as a SLURM task
  2025-09-22 09:20:10 | INFO     | [transcribe] Submitted with Slurm job ID 847632
  ...
  2025-09-22 09:20:10 | INFO     | [transcribe] Status changed: INACTIVE -> PENDING (Reason: (None))
  ...
  2025-09-22 09:20:31 | INFO     | [transcribe] Status changed: PENDING (Reason: (None)) -> ACTIVE (0 workers)
  ...
  2025-09-22 09:30:33 | WARNING  | [transcribe] Workers pending more than 10 minutes: 847645, 847649
  ...
  2025-09-22 09:32:29 | INFO     | [transcribe] Status changed: ACTIVE (0 workers) -> ACTIVE (1 workers)
  ...
  2025-09-22 09:40:36 | WARNING  | [transcribe] Workers pending more than 10 minutes: 847649, 847653
  

[yoonspark]

The first improvement (adding a log message for informing completion of all staged files) was implemented by #35.

[Nina-mvH]

The last improvement was implemented in #113

[yoonspark]

The remaining improvement (run-level summary) requires implementation of #122, which is marked as a dependency.