D110 — Topic-owned decision records and GitHub-owned project state

Decision. The monolithic docs/decisions.md becomes a short router to topic-owned registers under docs/decisions/. Each D entry has one owner and a stable dNN anchor; there is no duplicated global title/status table. The obsolete roadmap page is removed. Issues own bugs, enhancements and plan status; pull requests and releases own delivery; CHANGELOG.md summarizes completed user-visible changes.

Plan issue titles reserve D numbers before implementation. Allocation therefore checks both existing records and all plan issue titles. Implementation writes the final entry to the one topic named by the plan. PRs in unrelated topics no longer conflict merely because they both add decisions.

Rationale. The old register had grown beyond 1,700 lines while its duplicated quick index stopped at D49, disagreed with later entries and hid stale product claims. The roadmap repeated the same completed history while pointing mutable work back to GitHub. Topic ownership keeps searches bounded and makes each change update one current-state page, one rationale record and one external status object at most.

Consequences. docs/index.md, MkDocs navigation, contributor guidance, plan/implementation skills and the Plan issue template use the same routing. Documentation tool-name validation walks nested current-state pages but skips historical decision registers.