feat(feature-flags): generalize driver-side cache - #974

Verdict: 1 Low

Solid, well-tested generalization of the feature-flag cache — the typed getters correctly exclude bool-as-int, enforce fixed-width ranges, and reject NaN/inf, and the shared _CacheState + RLock refresh coordination is sound. One low-severity lifecycle note: get_instance is now created eagerly per non-kernel connection while remove_instance has no production caller, so the refresher executor/cache is never cleaned up.

Verdict: 1 Low

Looks solid overall — the typed getters are correct and well-covered (bool/int range via ctypes, double finiteness, strict list typing), and the workspace-keyed sharing with host fallback is sensible and tested. One low-severity lifecycle concern: remove_instance (which shuts down the shared refresh executor and evicts cache state) has no production caller, so the executor and per-workspace cache leak for the process lifetime. Minor nit below.

Nit (no anchor needed): the typed getters' default_value parameters (get_int32/get_int64/get_double/get_string/get_string_list, and _get_int) lack type hints, unlike the annotated return types; adding them would match the repo's type-hint convention (CONTRIBUTING.md).

Verdict: 1 Low

Looks good — a clean, well-tested generalization of the feature-flag cache (shared _CacheState per workspace, typed JSON getters, refresh dedup, pre-session reader). One low-severity note: get_bool is a stricter parser than the str(...).lower() == "true" telemetry gate it replaces, so the telemetry flag now depends on the server emitting a bare lowercase JSON boolean. Nit (summary-only): the typed getters annotate return types but leave default_value/integer_type/name params untyped in _get_int, get_int32/64, get_double, etc. — CONTRIBUTING.md asks for type hints; adding default_value: Optional[int] = None style annotations would keep them consistent with get_bool/get_string.