* docs(claude-code): tidy configuration reference and sync README
Add missing settings (retainMode, retainToolCalls, retainTags,
retainMetadata, embedPackagePath, llmApiKeyEnv, agentName, and
several recall options) that existed in code but not in docs.
Restructure config tables with prose introductions, clearer
descriptions, and consistent layout across both files.
* refactor(claude-code): remove recallTopK setting
Unused client-side cap — Hindsight server already controls result
count via recallBudget and recallMaxTokens.
* fix(python-client): async=true was silently ignored on retain calls
The hand-written client wrapper passed `async_=retain_async` to
RetainRequest, but the generated Pydantic model uses `var_async` as the
Python field name (with `alias="async"`). The `async_` kwarg didn't
match either the field name or the alias, so Pydantic silently ignored
it — every retain call ran synchronously regardless of the flag.
This has been broken since the client was first introduced (6073ac4f),
not a regression.
Also adds unit tests that verify the async field serializes correctly
in the request JSON, preventing future regressions.
c9ff37dcbf