Bootstrap a new document shelf at shelf_path.

Creates the directory layout (docs/, INDEX.md, .docshelf.json, .gitignore), pre-creates any default_categories, and stores the github_remote so generated INDEX entries link to raw GitHub URLs.

Idempotent — safe to call on an existing shelf to update metadata.

Add a PDF or Markdown file to the shelf and refresh INDEX.md.

• .pdf is converted to Markdown (pymupdf4llm by default; pass quality='high' to use marker-pdf).

• Documents larger than 50 KB with multiple H2 headings are split into one file per section (turn this off with split=False).

• INDEX.md is regenerated automatically. The caller still owns the git commit / push step.

Regenerate INDEX.md from the current on-disk shelf state.

Useful after manual edits to docs/ or .docshelf.json.

Plain-text search across every Markdown file in the shelf.

Tokens are space-split; each must appear (case-insensitive) for a hit to count. Results include the relative path, a 200-char snippet, and — if a GitHub remote is configured — the raw URL so the model can fetch the matching file directly.

List documents grouped by category.

Pass a category to filter; omit it to list everything.

Standalone PDF → Markdown conversion (no shelf, no INDEX update).

Use when you want the converted file but don't yet want to commit it to a shelf. Optionally splits the result by H2.