Implement min/max list length validation

[ipspace]

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[Copilot]

Pull request overview

This PR extends netlab’s attribute validation for list-typed attributes by adding support for minimum and maximum list length constraints, along with updated coverage tests and developer documentation describing the new validation options.

Changes:

• Add min_length / max_length support to the list type validator (must_be_list).
• Replace the previous empty-list error coverage with a more comprehensive list validation error fixture (attr-list.yml / .log).
• Document the new list validation options in the developer validation types reference.

Reviewed changes

Copilot reviewed 2 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/coverage/errors/attr-list.yml	New coverage error topology exercising empty/non-empty, nested-list, and min/max list length behaviors.
tests/coverage/errors/attr-list.log	Expected error output for the new list validation coverage scenario.
tests/coverage/errors/attr-empty-list.yml	Removed older, narrower empty-list coverage fixture (superseded by attr-list).
tests/coverage/errors/attr-empty-list.log	Removed expected log for the superseded empty-list fixture.
netsim/data/types.py	Implements min_length / max_length checks in must_be_list.
docs/dev/validation-types.txt	Documents min_length / max_length list validation options and adds a footnote clarifying scalar-to-list conversion.