Add EOS free-space pre-flight check (NAPPS-1091)

[jtdub]

Summary

• Adds a pre-flight free-space check to EOSDevice.file_copy and EOSDevice.remote_file_copy so transfers fail fast when flash lacks room for the image.
• Establishes a cross-driver pattern on BaseDevice (_get_free_space seam + concrete _check_free_space helper) so companion work for IOS, NXOS, JUNOS, and ASA only has to implement the per-platform probe.
• Makes FileCopyModel.file_size a required field with an optional file_size_unit (bytes / megabytes / gigabytes), mirroring how callers already declare the checksum. file_size_bytes is computed once in __post_init__.

Implementation notes

• NotEnoughFreeSpaceError gained optional required / available / file_system kwargs; the existing positional (hostname, min_space) signature is preserved so F5Device._check_free_space keeps working untouched.
• EOS _get_free_space parses the trailing (N bytes free) token from dir output; the file_system argument is accepted for API parity but unused because EOS only exposes a single practical filesystem.
• remote_file_copy (HTTP / HTTPS / SCP / SFTP / FTP / TFTP) compares src.file_size_bytes against _get_free_space() after the scheme/URL validation and enable-session setup but before the copy command is built or sent — so an oversized transfer never reaches the device's copy machinery.
• file_copy compares os.path.getsize(src) against _get_free_space() after file_copy_remote_exists() reports the file is missing.

Breaking change

• FileCopyModel(...) now requires file_size. Every in-repo call site (tests, integration, docs) has been updated; external consumers will see a TypeError until they add the kwarg.

Not in this PR

• IOS / NXOS / JUNOS / ASA implementations are tracked separately; this PR only wires EOS in and lays the base-class seam.

Test plan

• poetry run pytest tests/unit -q — 651 passed (up from 639; 12 new)
• poetry run ruff check pyntc tests
• poetry run ruff format --check pyntc tests
• poetry run pylint pyntc — 10.00/10
• poetry run towncrier build --draft renders the changes/370.* fragments cleanly
• Manual integration run against a lab cEOS node (tests/integration/test_eos_device.py) — set EOS_HOST/EOS_USER/EOS_PASS + per-protocol URL vars + FILE_CHECKSUM/FILE_SIZE/FILE_SIZE_UNIT; the new free-space tests include an oversized-transfer case that expects NotEnoughFreeSpaceError.

🤖 Generated with Claude Code

[mattmiller87]

I am of the opinion that the file size is a required piece of information to add this feature. It is similar to file checksum as a required field. To do the copy, you need to know certain things about the file.

To leave the file size optional, likely adds more complexity in the code to process and determine file size.