bug: honor defaults on repeatable positional declarations

[codeforester]

Goal

honor defaults on repeatable positional declarations.

Background and verified evidence

Review date: 2026-09-17. Reviewed commit: 38042cbf23b9380c626aae6c9fe168f97096c1cc. Parent: #214.

base_cli_positional p "" things repeatable=true default=fallback succeeds, but base_cli_parse p -- returns 0 with an empty BASE_BASH_LIBS_CLI_RESULT_POSITIONALS. The repeatable branch of __base_bash_libs_cli_apply_positionals__ reads default but never applies it. These attributes are advertised together in lib/bash/cli/README.md.

Scope and acceptance criteria

• Apply the declared default when no repeatable values are supplied, with the same enum/validator behavior as other defaults.
• Specify and test the interaction between required, repeatable, defaults, preceding positionals, and explicit empty values.
• Keep table declarations and direct declarations equivalent.

Validation

Reproduce the no-argument invocation above, exercise explicit and invalid defaults, and run CLI BATS/full validation.

Non-goals

No unrelated API expansion or automatic release publication. Preserve immutable published assets and unrelated consumer files.

Project fields

• Status: Ready
• Priority: P2
• Area: CLI
• Initiative: Adoption Polish
• Size: S
• Milestone: v2.2.0
• Target date: unset; no delivery date has been committed.
• Type: Bug

Agent assignment

Assignee: codeforester. This is review/backlog intake; implementation has not started.