feat(adapters): implement cloud storage range adapters and enterprise proxy tunnels

[archittmittal]

Objective & Overview

Implement protocol adapters for direct range downloads from cloud object stores (AWS S3, Google Cloud Storage, Azure Blob Storage) and enterprise network proxies (SOCKS5, HTTP CONNECT).

Technical Specification & Design

• Cloud Protocols:
  • AWS S3: SigV4 signature headers for range GETs
  • GCS: gs:// OAuth2 token authorization
  • Azure: az:// Shared Key and SAS range requests (x-ms-range)
• Enterprise Proxies:
  • SOCKS5 (RFC 1928) handshake and remote DNS
  • HTTP CONNECT proxy tunneling with custom CA bundles

Key Deliverables & Module Breakdown

• src/adapters/s3_adapter.py: AWS S3 range adapter
• src/adapters/gcs_adapter.py: GCS range adapter
• src/adapters/azure_adapter.py: Azure Blob adapter
• src/adapters/proxy_adapter.py: SOCKS5 and HTTP CONNECT proxy adapter

Acceptance Criteria & Checkpoints

• SigV4 test vectors passing for AWS S3
• GCS and Azure range requests correctly formatted
• Proxy tunneling verified with mock SOCKS5 and HTTP proxies

Documentation References

• Cloud & Protocol Adapters
• Security