1.1.0

Changed

• Histogram bucket counts and the running sum are now backed by a single OTP atomics array per histogram (slot 1 = IEEE-754 bits of the sum via CAS retry, slots 2..N+2 = signed int64 bucket counts via atomics:add/3). Drops the per-bucket NIF resources and makes get_histogram / collect ~1.5x faster; observe_histogram is unchanged. Counters, gauges, and up-down counters remain on the NIF path.
• Histogram count and per-bucket count fields in the collected map are now integers, matching the instrument_metrics_exporter spec which already declared them as integer(). Callers that compared these fields with =:= against float() values must update their expectations.

Added

• instrument_atomics module: thin wrapper over atomics providing signed-integer slots and IEEE-754 double slots via bit-cast with a CAS retry loop.