A minimal in-memory fixed-window per-tenant rate limiter — the default a
single-instance host can wire without a store. NOT cross-isolate: a
DO-per-run/thread host that needs a shared window uses a D1/KV-backed limiter
behind the same SignalRateLimiter seam (the store's reach IS the cap's
reach, exactly as breakwater's rate-limit policy documents).
A minimal in-memory fixed-window per-tenant rate limiter — the default a single-instance host can wire without a store. NOT cross-isolate: a DO-per-run/thread host that needs a shared window uses a D1/KV-backed limiter behind the same
SignalRateLimiterseam (the store's reach IS the cap's reach, exactly as breakwater's rate-limit policy documents).