Refactor blob storage to use UUID primary keys and implement streaming chunking

- Changed blob table to use ID (UUID) as primary key instead of hash
- Blob records are now created at packing start, enabling immediate chunk associations
- Implemented streaming chunking to process large files without memory exhaustion
- Fixed blob manifest generation to include all referenced blobs
- Updated all foreign key references from blob_hash to blob_id
- Added progress reporting and improved error handling
- Enforced encryption requirement for all blob packing
- Updated tests to use test encryption keys
- Added Cyrillic transliteration to README

CLAUDE.md

@@ -26,3 +26,9 @@ Read the rules in AGENTS.md and follow them.
 * Do not stop working on a task until you have reached the definition of
   done provided to you in the initial instruction.  Don't do part or most of
   the work, do all of the work until the criteria for done are met.
+
+* We do not need to support migrations; schema upgrades can be handled by
+  deleting the local state file and doing a full backup to re-create it.
+
+* When testing on a 2.5Gbit/s ethernet to an s3 server backed by 2000MB/sec SSD, 
+  estimate about 4 seconds per gigabyte of backup time.