feat: add OpenSpec specs and changes for ASW restructure

Specs: repo-structure, 10 framework layer specs, packs, site.
Changes: repo-restructure (10 tasks), css-refactor (12 tasks),
legacy-import (proposal + triage categories).

Supersede docs/css-refactor-plan.md in favor of OpenSpec change.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

openspec/specs/framework/components/spec.md

@@ -0,0 +1,26 @@
+# Spec: Components (Layer 05)
+
+File: `src/layers/05-components.css`
+
+## Purpose
+
+Compound UI patterns that go beyond single-element semantics. These are patterns that require specific HTML structures.
+
+## Scope
+
+### In scope
+- `dialog` — modal dialogs
+- `details` / `summary` — accordion pattern
+- Breadcrumb navigation (`[data-role="breadcrumb"]`)
+- Step indicators (`[data-role="steps"]`)
+
+### Out of scope
+- Single HTML elements with default styling (→ landmarks, typography, forms)
+- Sidebar navigation (→ navigation layer)
+- Charts (→ charts layer)
+- Data-attribute vocabulary (→ data-attributes layer)
+
+## Constraints
+
+- This layer should be small — if a pattern can be expressed by a semantic HTML element alone, it belongs in landmarks or typography, not here
+- References only semantic aliases from `01-tokens.css`