Major SKILL.md rewrite:
- Fast path: skip extraction when graph exists and user asks a question
- Gemini backend replaces Kimi as default external LLM
- All file I/O uses ensure_ascii=False + encoding="utf-8"
- Monorepo support via per-subfolder extraction + merge
- Obsidian/HTML export via CLI instead of inline Python
- Node ID format includes parent dir to prevent ghost duplicates
- file_type gains "concept" as valid value
- Subagent chunk paths must be absolute
- --help flag prints usage and stops
- Large corpus gate raised from 200 to 500 files
Bumps gstack submodule to 026751e.
Co-Authored-By: Claude <noreply@anthropic.com>