* feat(memory): integrate FTS5 retrieval adapter
* deps: add jieba as default dependency for Chinese tokenization
Without jieba, FTS5 unicode61 tokenizer treats entire Chinese sentences
as single tokens, making single-character or sub-phrase searches
impossible (e.g. '吃' or '油泼面' returns 0 hits against
'用户喜欢吃油泼面'). jieba segments Chinese text into meaningful tokens
before indexing.
* fix(memory): avoid treating hyphens as FTS5 operators
* feat(memory): make Chinese tokenization optional
* fix(memory): warm every requested retrieval scope
* fix(memory): close retrieval resources on shutdown
* fix(memory): close backend when shutdown flush fails
* fix(memory): recreate corrupt retrieval index
* fix(memory): tolerate partial retrieval rebuilds
* fix(memory): warm retrieval index in background
* fix(memory): preserve shutdown flush budget
* fix(memory): stop retrying partial lazy rebuilds
* fix(memory): close retrieval through storage
* refactor(memory): simplify retrieval scope limit
* docs(memory): clarify retrieval shutdown lifecycle
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>