When vars are marked with neededFor="activation" or "partitioning", they
need to be available early in the boot process. However, the populate_dir
methods in both sops and password_store secret backends were only calling
self.get() which only retrieves secret vars from the .../secret path.
This caused public vars (stored at .../value) to fail with "Secret does
not exist" errors when trying to upload them.
The fix uses file.value property instead, which properly delegates to the
correct store (SecretStore or FactStore) based on whether the file is
marked as secret or public.
Fixes affected all neededFor phases in both backends:
- sops: activation and partitioning phases
- password_store: activation and partitioning phases
a569a1d147