Add bibliographic ETL pipeline for WoS-style standardization

[saniatulnaimahuq]

This pull request adds a bibliographic ETL pipeline for converting heterogeneous bibliographic records into a Web of Science-like schema for Bibliometrix-Python.

Main additions:

• Added a source-agnostic ETL pipeline under www/services/bibliometrix_etl
• Added mapping dictionaries for local bibliographic files and OpenAlex records
• Added extraction support for local files and OpenAlex API records
• Added transformation logic for WoS-like field tags such as TI, AU, PY, SO, DI, AB, TC, and SR
• Added cleaning support for DOI values, missing values, publication years, citation counts, and multi-value fields
• Added validation module to check required columns, null values, and multi-value field handling
• Added analysis validation script to test standardized outputs with bibliometric-style analyses
• Added generated CSV outputs and validation reports as execution evidence

Validation completed successfully for:

• Base-level local Scopus-like CSV pipeline
• Advanced-level OpenAlex API pipeline

Terminal output confirmed:

PASSED: Standardized data is valid.
ANALYSIS VALIDATION COMPLETED
PROJECT EXECUTION COMPLETED