D010: Build-in-the-open knowledge graph

Context: Saif wants to document the whole project as an Obsidian-like graph of connected notes, rendered on the site and working in real Obsidian.

Decision: Maintain a real Obsidian vault (/brain) documenting every decision from day one, and render it on the site as an interactive force-directed graph. Implementation: Knowledge Graph.

Why: Hiring managers rarely see how someone decided. A living decision graph shows judgment, trade-off awareness, and systems thinking directly, the "I reason / I document" meta-proof of North Star - Site as Proof. It also demonstrates real engineering (vault parsing, wikilink resolution, force-graph rendering) and pairs naturally with D009 - SEO and AI Crawlers (crawlable, citable reasoning).

Trade-offs: content discipline required, a note per decision, written when the decision is made. Vault is build-time static so it scales to hundreds of notes trivially. Public-scope/rawness open (Open Questions #7). This vault is the first instance of the feature.