v0.1.0

• Initial release
• Append-only event recording with MeterBox.record
• Aggregation queries: total, breakdown, over_cap?, events_for
• Per-meter aggregation types (sum, count, latest, max, min, mean, count_distinct)
• Typed dimension validation (required, allowed values)
• Idempotent inserts via idempotency_key
• Polymorphic owner support
• Thread-safe configuration lifecycle
• Rails install generator (rails generate meter_box:install)