Roll up integration into dev

[loning]

Release Notes

This rollup merges PR #128 for issue #127, adding opt-in engine-owned Lua line coverage for self-test runs.

Added

• fkst-framework --self-test --coverage <dir> can emit Lua line coverage owned by the engine runtime.
• Coverage output includes coverage.json and lcov.info line records for downstream coverage gates.
• Lua chunks are mapped with stable @<owner-root-relative-path> source names so mlua line-hook hits resolve to repository files.
• Production coverage excludes test/generated chunks and remains line-granularity only.

Notes

• Coverage is opt-in, preserving normal self-test execution without hook overhead.
• The final implementation keeps the line-hook hot path lightweight and fixes source mapping for the legacy department runner path.

中文简记

• 新增 --self-test --coverage 的引擎侧 Lua 行覆盖率输出。
• 输出 coverage.json 与 lcov.info，用于后续 package 侧覆盖率门禁。
• 覆盖率仅为 line coverage；测试文件和生成 chunk 不计入生产覆盖率。
  ⟦AI:FKST⟧