Public thinking page — forks before decisions

Status: Accepted

Context: /todo mixed ops tasks with one-line votes. docs/THINKING.md held richer "this vs that" reasoning but had no public URL. Visitors should see thought process, not be asked to answer open questions yet.

Decision: Sync docs/THINKING.md to public /thinking (Context, Fork, Leaning, Status). Keep /todo as building-in-public checks + short voteable directions with optional context. Resolved forks link to ADRs on /decisions.

Consequences: sync-docs.js generates thinking/index.html. Social drafts for thinking blocks link to /thinking. No Ask field on thinking blocks for now.