chore: translate backend logs ，parse and extract repetitive progress bar logs to status field

[duanchy3]

…glish

[Copilot]

Pull request overview

This PR translates backend logs, error messages, and exception messages from Chinese to English across multiple service and API endpoint files. The translation improves code accessibility for international developers and standardizes the codebase language.

Changes:

• Translated error messages and exceptions in dataflow engine and pipeline executor services
• Translated logging statements in registry services (operator, pipeline, dataset)
• Translated API endpoint summaries, docstrings, and error messages

Reviewed changes

Copilot reviewed 7 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
backend/app/services/ray_pipeline_executor.py	Translated error messages for missing prompt classes, parameter processing failures, and operator initialization failures
backend/app/services/pipeline_registry.py	Translated initialization log messages and docstring for registry file initialization
backend/app/services/operator_registry.py	Translated warning and info log messages for operator loading, scanning, and error handling
backend/app/services/dataset_registry.py	Translated log message for dataset reading operation
backend/app/services/dataflow_engine.py	Translated error messages for serving configuration, storage initialization, and dataset operations
backend/app/api/v1/endpoints/operators.py	Translated API summaries, docstrings, log messages, and inline comments
backend/app/api/v1/endpoints/datasets.py	Translated API summary, docstring, and error message for directory listing endpoint
backend/app/.DS_Store	macOS system file inadvertently included
backend/.DS_Store	macOS system file inadvertently included
.DS_Store	macOS system file inadvertently included

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