Fix test task structure and option parsing

[c0da-ricon]

Finding

The parallel test task added in #8 mixes public task metadata, argument reconstruction, target resolution, BATS option interpretation, dependency policy, reporting, and execution in one large entrypoint.

Its second pass over raw arguments also mistakes option values for wrapper controls. For example, mise run test --filter --jobs treats the filter regex as a job flag, and a filter value matching a suite shorthand can be rewritten as a test path.

Fix

• keep .mise/tasks/test as a thin Usage/argument adapter;
• move the readable command workflow into libexec/test;
• parse BATS 1.13 option values before interpreting parallel controls or suite targets;
• add regressions for missing job values and filter values that resemble flags or suite names;
• document the .mise/tasks / libexec / shared lib boundaries;
• remove bats-test-task from Template's configured lints because its current direct-invocation assumption rejects this intended structure.

The generic lint split is tracked separately in KnickKnackLabs/codebase#78.

Validation

• focused test-task suite: 13/13
• full default-parallel suite: 16/16
• full serial suite: 16/16
• configured codebase lints: 8/8
• README generation check
• Bash syntax and git diff --check

Fix-it for #8. The parent author retains the merge decision.