fix(analyzer): project manifest version for RP3

[agentsope]

Summary

• project the version field from SKILL.md frontmatter into the bounded manifest
• add a regression test that exercises real frontmatter through build_context before running the RP3 analyzer
• update the manifest parser docstring to include the projected field

Before this change, RP3 ran successfully but could not observe version, so values such as "*" produced no finding.

Fixes #472.

Testing

• PATH="$PWD/.venv/bin:$PATH" make test-unit (3979 passed, 14 skipped, 38 deselected, 4 xfailed)
• PATH="$PWD/.venv/bin:$PATH" make lint format-check
• manual no-LLM CLI repro: version: "*" now emits RP3