- kb-config::apply_env now covers every leaf key in `Config` via an
explicit grep-friendly match block (one arm per leaf), keyed
`KB_<SECTION>_<KEY>`. Booleans flow through a shared `parse_bool` helper.
Numeric leaves silently keep their prior value on parse failure so a
malformed env entry can't crash startup.
- New tests: env_unknown_key_is_ignored,
env_overrides_chunking_target_tokens,
env_overrides_models_llm_endpoint_and_temperature,
env_overrides_indexing_watch_filesystem_bool.
- kb-app::logging::init now returns `Result<WorkerGuard>` instead of
`Result<Option<WorkerGuard>>` — the inner `Option` was always `Some` so
the wrapper was dead. kb-cli/main.rs collapses the call from
`.ok().flatten()` to `.ok()`, preserving fail-soft semantics on logging
init.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the kb-config crate per design §6. Provides the frozen Config
schema (§6.4) with serde + toml round-trip, defaults() that exactly
match the reference values (e.g. score_gate=0.30, target_tokens=500,
embedding.dimensions=384, rrf_k=60), and XDG path resolvers that honor
XDG_CONFIG_HOME / XDG_DATA_HOME / XDG_CACHE_HOME / XDG_STATE_HOME.
Layer order in load(): defaults → file → env (KB_<SECTION>_<KEY>);
CLI overrides apply later in kb-cli. Env mapping covers the keys
needed by P0 smoke tests; the rest land as their config sections wire
up.
5 unit tests cover serde round-trip, defaults pinned to design,
KB_RAG_SCORE_GATE / KB_SEARCH_DEFAULT_K env override, and
XDG_CONFIG_HOME handling.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
