Refactor and clean up documentation

docs/adr/0001-record-architecture-decisions.md

@@ -0,0 +1,23 @@
+# ADR-0001: Record architecture decisions as ADRs
+
+**Status:** Accepted
+**Date:** 2026-07-13
+
+## Context
+Architectural reasoning made during design (pattern choices, rejected
+alternatives, trigger conditions for revisiting) is lost if only the final
+state is documented.
+
+## Decision
+We keep a living overview in docs/policy/architecture.md describing current
+intended state, and immutable, numbered ADRs (Nygard format) in docs/adr/
+recording each significant decision, its alternatives, and its consequences.
+Changed decisions get a new ADR that marks the old one Superseded.
+
+## Alternatives considered
+- Overview doc only: loses the "why" and the rejected options.
+- arc42 / RFC-style design docs: heavier than warranted for a solo repo.
+
+## Consequences
+Small ongoing writing cost; durable reasoning trail; cheap onboarding for
+future contributors (including future-us).