Dataset download bug fix

[sanjaychelliah]

Issue 1: Silent Exception Swallowing ✅ FIXED

Problem: ThreadPoolExecutor wasn't checking for exceptions.
Solution: Added proper exception handling with future.result() to catch and log all failures.

Issue 2: Thread-Safety Race Condition ✅ FIXED (NEW)

Problem: Multiple threads writing to the same ZipFile object simultaneously.
Error: Can't write to ZIP archive while an open writing handle exists.
Solution: Added threading.Lock() to synchronize all ZIP file writes.
Protected operations:

_save_image_to_archive() - line 148
_save_text_to_archive() - line 164
_save_audio_to_archive() - line 183
_save_video_to_archive() - line 206
_save_annotation_to_archive() - line 231

Issue 3: Timeout Handling ✅ FIXED

Problem: No timeouts on HTTP requests.
Solution: Added 60s timeout for images/text/audio, 120s for videos.

Issue 4: Detailed Error Logging ✅ FIXED

Problem: No visibility into what failed or why.
Solution: Added comprehensive logging with input IDs and error messages.

[github-actions]

Package	Line Rate	Health
clarifai	45%	❌
clarifai.cli	67%	➖
clarifai.cli.templates	46%	❌
clarifai.client	65%	➖
clarifai.client.auth	67%	➖
clarifai.constants	100%	✔
clarifai.datasets	100%	✔
clarifai.datasets.export	67%	➖
clarifai.datasets.upload	75%	➖
clarifai.datasets.upload.loaders	37%	❌
clarifai.models	100%	✔
clarifai.modules	0%	❌
clarifai.rag	0%	❌
clarifai.runners	53%	➖
clarifai.runners.models	64%	➖
clarifai.runners.pipeline_steps	41%	❌
clarifai.runners.pipelines	77%	➖
clarifai.runners.utils	62%	➖
clarifai.runners.utils.data_types	72%	➖
clarifai.schema	100%	✔
clarifai.urls	60%	➖
clarifai.utils	60%	➖
clarifai.utils.evaluation	16%	❌
clarifai.workflows	95%	✔
Summary	61% (9969 / 16295)	➖

Minimum allowed line rate is 50%