v1.10.0

[1.10.0] — 2026-07-27

The dense-grid fill primitive (ADR-026) — unblocks pandas-free FAO ingestion (#203).
Additive MINOR; CONFORMANCE_FLOOR stays 1.0.0.

Added

• frame.reindex_fill(other, *, fill_value) on all three sibling frames
  (PredictionFrame/FeatureFrame/TargetFrame, WET per ADR-011): align to other's
  rows with no superset requirement — present rows pass through bit-exact, absent
  rows get the caller's fill_value broadcast across the trailing axes (NaN legal;
  keyword-only and required — no silent default, ADR-009). The result's index is
  other; metadata (and feature_names) preserved. Owns the -1-sentinel scatter once:
  a consumer hand-rolling values[pos] silently picks the last row for absent cells.
  Inherits the C-21 row-uniqueness stance (unique rows assumed in self; duplicate
  target rows allowed and repeat).
• SpatioTemporalIndex.cartesian(times, units, level): the dense product-index
  constructor — every (time, unit) combination in canonical time-major order, from
  explicit arrays only (deriving them, e.g. "units of the last time step", is
  consumer policy). Fails loud on duplicated input values (a duplicated product input
  manufactures duplicate rows → undefined same-level joins, C-21).
• assert_reindex_fill_law in the published conformance suite (ADR-016): result
  index equals the target row-for-row; present rows bit-exact; absent rows equal the
  fill (NaN-safe); on a superset frame the fill degenerates to reindex.
• Consumer note: faoapi's dense_grid.py can now delegate (its last-step-entity rule +
  C-87 dropped-entity check stay consumer-side) and drop its pandas implementation
  (faoapi #242). Densification allocates the full dense buffer — a deliberate, costly
  act at grid scale (documented on both symbols).