* 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.