Add Version Headers to Binary Formats

[jns-ps]

Implement version metadata in binary blob format to enable clients to identify serialization schema and parse data correctly. Currently, blobs lack version information, forcing clients to guess parsing strategy or fail on format changes.

Confirmations

• Determined which binary formats require versioning
• Binary formats include version header (e.g., first 4 bytes as version identifier)
• Clients (external and internal) can detect version and route to appropriate parser
• Documentation updated with version header specification
• Unit tests cover version detection and parsing for multiple format versions

Out of Scope

• Migration of existing blobs (we are not live yet)
• Client library implementation of multi-version parsing (extra tasks)