Improve baseline resync logging

[koujl]

Eliminate inconsistent terminology, context, and severity levels across existing BR read/write logs. Add structured lifecycle, payload, retry, and failure records with consistent PG, shard, batch, blob, and block identifiers. Keep key object and payload transitions at INFO while moving per-blob details to TRACE to reduce routine log noise.

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 0% with 56 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (stable/v4.x@ec55254). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
...ib/homestore_backend/replication_state_machine.cpp	0.00%	25 Missing ⚠️
src/lib/homestore_backend/pg_blob_iterator.cpp	0.00%	16 Missing and 1 partial ⚠️
...lib/homestore_backend/snapshot_receive_handler.cpp	0.00%	14 Missing ⚠️
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Additional details and impacted files

@@              Coverage Diff               @@
##             stable/v4.x     #455   +/-   ##
==============================================
  Coverage               ?   54.94%           
==============================================
  Files                  ?       36           
  Lines                  ?     5344           
  Branches               ?      676           
==============================================
  Hits                   ?     2936           
  Misses                 ?     2109           
  Partials               ?      299           

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