`revision_forecast()` and `cv_revision_forecast()` appear to "ignore" `training_days` when called directly

From a quick skim of source code for training window handling:

- `revision_forecast()` appears to use `training_days` only in filepath generation.
- (`DelphiRF()` does `training_days`-related filtering before calling `revision_forecast()`, so the `DelphiRF()` function's fine.)
- `cv_revision_forecast()` doesn't appear to do the `training_days`-related filtering before calling `revision_forecast()`, so it seems it actually won't respect `training_days` unless the user manually performs that filtering ahead of time.

Read the implementations of `revision_forecast()`, `cv_revision_forecast()`, and `DelphiRF()` to trace where `training_days` filtering occurs. Compare the direct and cross-validation paths, then verify that both respect the requested training window, using any existing project checks for forecast behavior if available.

Written by the indexing model from the issue text.