Show how release-verify-rc loads the binary-exclude list in step 6

[justinmclean]

Summary

Step 6 of release-verify-rc says it scans for files matching the
binary-exclude list from release-build.md, but the command it emits hardcodes
a fixed pattern set and never reads that file.

Background

The step's prose points at adopter config as the source of the exclude list,
which is what makes the skill project-agnostic: a project with a different
prohibited-binary set is meant to configure it, not edit the skill. The emitted
command instead carries a fixed list of compiled Java classes, native shared
libraries and Python bytecode.

For an adopter whose release-build.md names anything outside that set, the
scan silently misses it while the step reports as though the configured list was
used. The step's classification output is fine; it is the gap between "from
release-build.md" and a hardcoded pattern list that misleads.

Either outcome closes this: show how the list is loaded and use it, or state
plainly that the pattern set is a fixed baseline and that release-build.md
supplies additions.

Where to look

• skills/release-verify-rc/SKILL.md around lines 429-440 - step 6, its prose
  and the emitted scan command.
• skills/release-verify-rc/SKILL.md line 351 - the RAT step, which shows how
  another step reaches into release-build.md for its configuration. It is the
  pattern to follow if the answer is to load the list.
• projects/_template/release-build.md - what an adopter actually configures,
  and under which heading.
• tools/skill-evals/evals/release-verify-rc/step-6-binary-exclusion/ - the eval
  cases, which will need to match whichever way this is resolved.

Acceptance criteria

• Step 6's prose and its emitted command agree about where the exclude list
  comes from.
• If the list is loaded from config, the step shows how, in the style of the
  RAT step.
• If the pattern set stays fixed, the prose says so and explains how
  release-build.md extends it.
• The step-6 eval cases still pass.
• uv run --project tools/skill-and-tool-validator --group dev skill-and-tool-validate
  passes.

Estimated effort

~2 hours for someone new to the codebase.

Getting started

New to Magpie? Start with
[Your first contribution](https://github.com/apache/magpie/blob/main/CONTRIBUTING.md#your-first-contribution).

Note: this issue was drafted by an AI-assisted mentoring tool and may contain
mistakes. A Magpie maintainer, a real person, will be the next to engage on it.
If something here looks wrong or unclear, please say so on the issue and a
maintainer will follow up. See
[CONTRIBUTING.md](https://github.com/apache/magpie/blob/main/CONTRIBUTING.md)
for how Magpie handles contributions.

[Shaurya2k06]

Happy to pick this up!
cc @justinmclean