Implements ObsidianConnector (filesystem auth, no OAuth) that walks a vault
directory for .md/.markdown/.txt files, parses YAML frontmatter via a
dependency-free parser, skips hidden dirs and binary files, and yields
Document objects with doc_type="note" and obsidian:// deep-link URLs.
Exposes an obsidian_search_notes MCP ToolSpec. 9 tests cover connection
state, vault traversal, hidden-dir/binary filtering, frontmatter extraction,
and registry wiring.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>