[0.4.0] - 2026-06-13

Added

• split_by_date(df, target_date, observation_days=28, evaluation_days=7, time_col="datetime"):
  new top-level utility function (from rfscorer import split_by_date) that splits a single
  interaction log into an observation/evaluation pair at target_date.
  Returns (df_obs, df_eval). Accepts the same datetime or integer time_col as the scorer.
• unit parameter to RecencyFrequencyScorer.__init__(): controls recency bin granularity.
  unit=7 gives weekly recency, unit=30 approximate monthly. Default unit=1 preserves
  the previous day-level behavior.
• Integer time_col support: time_col columns of integer dtype are now accepted in addition
  to datetime / string columns across fit(), transform(), and split_by_date().
• plot_marginal_probability(kind="er") and kind="ef": new 1-D marginal plot support for the
  empirical recency and frequency models.

Changed

• er_probability_ and ef_probability_ are now true 1-D outputs, mirroring the earlier
  mr / mf refactor. Breaking changes:
  • er_probability_: columns reduced to (recency, probability)
    (previously recency, frequency, probability after 2-D broadcast)
  • ef_probability_: columns reduced to (frequency, probability)
    (previously recency, frequency, probability after 2-D broadcast)
  • er_probability_dict_: keys changed from (r, f) tuple to int r
  • ef_probability_dict_: keys changed from (r, f) tuple to int f
  • predict(kind="er"): f argument is now ignored; r is clamped to recency_limit
  • predict(kind="ef"): r argument is now ignored; f is clamped to frequency_limit
  • plot_probability_surface(kind="er"|"ef"): now raises ValueError
    (use plot_marginal_probability() instead)
• empirical_probability_* attributes renamed to emp_probability_* for consistency with all
  other short-form kind prefixes. Breaking changes:
  • empirical_probability_ → emp_probability_
  • empirical_probability_table_ → emp_probability_table_
  • empirical_probability_dict_ → emp_probability_dict_
  • CSV column "empirical_probability" (from export_probability_csv(kind="all")) → "emp_probability"
  • The kind aliases "empirical", "empirical_recency", "empirical_frequency" are preserved.

Removed

• Python 3.10 support. Minimum supported version is now Python 3.11.
• er_probability_table_ and ef_probability_table_ attributes.
  These were 2-D broadcast grids produced by the previous implementation and are no longer generated.