Specialist skill for answering questions FROM the Obsidian vault — "how does X work", "why did we choose Y", "what do we know about Z", "find the docs about…". It owns the hidden per-project index (a catalog of every note with one-line summaries, in <vault>/.claude-docs/) and run log, reads the index first to locate relevant notes, then synthesizes a cited answer. Valuable answers can be filed back into the vault. Use whenever the user asks a question whose answer should live in the documentation, or asks to find/locate notes.
