Featurizer 1.0.1

Pure bug-fix release (semver PATCH under the ADR-0015 freeze). No feature
names change for any config that does not use the empty-list spelling —
the SQL/naming snapshot test is byte-identical.

Fixed

• transformations: [] / aggregations: [] were silently swallowed.
  The primitive-selection sites used config.get(...) or DEFAULT, which
  treats an explicit empty list as "unset": a config writing
  transformations: [] to suppress the transform layer silently got all
  17 defaults (reported live from triage-pg — ~2,500 unwanted
  CUM_SUM/ABS-composition columns). An empty list now suppresses that
  layer: transformations: [] passes features through unchanged
  (byte-identical output to the [identity] workaround spelling, which
  keeps working), and aggregations: [] builds zero aggregation features
  (legal-but-weird by decision — the planner already emits no CTE/join for
  a zero-feature relationship). Absent or null keys keep applying the
  curated defaults. Covered DB-free and with executing integration tests;
  documented in the configuration reference.
  Downstream note: triage-pg pins the engine version into artifact
  identity (its ADR-0016), so its pin bump after this release
  intentionally invalidates feature caches — no coordination needed; no
  columns are renamed.