docs: Add Data Source Inventory and Ingestion Architecture Analysis (#98)

[23shivay]

Summary

This PR fulfills Task #98: Create Inventory of Data Sources and Define Standard Data Contracts, a sub-task under the broader initiative to design a scalable and decoupled ingestion framework for real-time and batch data.

Key Outcomes

Created a complete inventory of current data sources
Classified each as real-time or batch
Documented data types, formats, and ingestion frequency
Outlined architecture fit and ingestion approach per source
Included initial design of real-time and batch ingestion pipelines
Identified sources requiring transformation (e.g., XML → JSON)

Artifacts Included

• source-summary-table.png: Source-wise frequency, format, and structure
• architecture-fit-table.png: Architecture design fit for each source
• architecture-diagram.jpg: Conceptual ingestion architecture for real-time and batch sources

Images:

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Notes

• Data formats and transformation points are defined with future schema standardization (e.g., JSON Schema, Avro) in mind.
• The current scope focuses on documentation and analysis; implementation will follow in subsequent tasks.

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cc @mvadodariya