v0.1.0

[0.1.0] - 2026-06-07: full assertion surface

The full surface: a queryable MeasurementSet, multi-instrument MeterCapture, meter-introspection
MeterInspector, baseline deltas, and the complete Assert.That assertion vocabulary across all three.

Added

• MeasurementSet (core): an immutable, queryable set of captured measurements with counter-style
  (Total) and histogram-style (Sum/Min/Max/Average) aggregates, raw Values/All, ordered and
  order-insensitive sample comparisons, tag and instrument narrowing (Tagged/ForInstrument), range and
  tag predicates, and a deterministic ToSnapshotString projection.
• MeterCapture (core): a meter-wide bundle composed from per-instrument captures, built fluently
  with For + Add, queried per instrument or across all via Measurements, with RecordObservable
  for observable gauges.
• MeterInspector (core): discovers which instruments a meter publishes
  (PublishedInstrumentNames/IsPublished/PublishesAll) via a short-lived MeterListener.
• InstrumentCapture (core): expanded with OfName/OfObservable construction, Total/LastValue,
  tag queries (Tagged/HasMeasurementTagged), baseline deltas (Snapshot/Since + MeasurementBaseline),
  RecordObservable, and WaitForAsync.
• MetricsAssertions.TUnit (adapter): the full Assert.That(...).Has* vocabulary (counter and
  up-down-counter totals, measurement counts, emptiness, last value, histogram sum/average/range, exact and
  order-insensitive sample sets, and tag-consistency) over InstrumentCapture, MeasurementSet, and
  MeterCapture.
• Failure diagnostics: every assertion dumps the captured measurements (instrument, value, tags,
  timestamp) under the failure, so a mismatch shows what was actually recorded, not only the mismatched
  scalar.
• Hardening: tolerance arguments are validated (finite, non-negative), inverted range bounds are
  rejected, baselines are bound to their originating capture, duplicate MeterCapture instrument names
  dispose the prior capture, and unknown meter-capture instruments fail as assertions rather than throwing.

Changed

• Breaking: InstrumentCapture.Measurements now returns a MeasurementSet instead of
  IReadOnlyList<CapturedMeasurement>. Use Measurements.All for the underlying list, or the new query
  surface directly.