Improved Session Persistence Reliability

What: Removed client-side duplicate UUID checking in favor of server-side validation

Details:

• Previously, the client would skip uploading session entries if their UUID was already fetched
• This client-side cache could become stale in multi-client scenarios
• Now all entries are uploaded, and the server handles deduplication via Last-Uuid headers and 409 conflict detection
• Simplifies retry logic and handles partial fetches more robustly
• Evidence: Function refactor from V8B() at line 397227 to ZPB() at line 436288

Why this matters: Session persistence is more reliable when multiple processes or partial fetch operations are involved.