[boriskozak]

Fixes #427

Passing a directory as dotenv_path to load_dotenv (or dotenv_values / get_key) silently loaded nothing, even with verbose=True. The CLI half of this was fixed in #441, but the library half stayed silent.

Now DotEnv._get_stream logs a warning when the given path exists but is not a regular file or FIFO:

python-dotenv could not load configuration file /path/to/dir: it is not a file.

Return values are unchanged (False / {}), so the lenient missing-file contract is preserved, and an explicitly passed stream still takes precedence over the path. The old misleading "could not find configuration file" info message no longer fires for this case under verbose=True.

Testing: 3 new tests in tests/test_main.py (directory warns for load_dotenv with verbose on/off, dotenv_values, and stream-takes-precedence). Full suite: 156 passed, 3 skipped, 1 failed (test_load_dotenv_in_current_dir, fails identically on clean main in this environment). ruff check and ruff format --check pass.