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/tokens/spec.md

@@ -0,0 +1,77 @@
+# Spec: Tokens (Layer 01)
+
+File: `src/layers/01-tokens.css`
+
+## Purpose
+
+Pure design token definitions. Aliases Open Props primitives to semantic names. Contains only `:root {}` variable declarations — no rules, no selectors, no styling.
+
+## Open Props Dependency
+
+ASW builds on Open Props as its primitive token source. Open Props provides:
+- Color scales: `--color-0` through `--color-16`
+- Size scale: `--size-1` through `--size-15`, `--size-px-1` through `--size-px-12`
+- Font sizes: `--font-size-0` through `--font-size-8`
+- Font weights: `--font-weight-1` through `--font-weight-9`
+- Shadows: `--shadow-1` through `--shadow-6`
+- Border sizes: `--border-size-1` through `--border-size-5`
+- Animations, easings, gradients, and more
+
+**Version:** tracked in `vendor/open-props/VERSION`
+
+## Aliasing Contract
+
+Every Open Props primitive used in the framework MUST be aliased through this file. Downstream layers (02+) MUST reference semantic aliases, never primitives.
+
+```css
+/* YES — downstream layers use this */
+color: var(--text);
+font-weight: var(--weight-bold);
+padding: var(--space-4);
+
+/* NO — never in layers 02+ */
+color: var(--color-6);
+font-weight: var(--font-weight-7);
+padding: var(--size-3);
+```
+
+## Token Categories
+
+### Colors
+- `--surface`, `--surface-alt` — background colors
+- `--text`, `--text-muted` — foreground colors
+- `--accent`, `--accent-hover` — interactive/brand color
+- `--border`, `--border-muted` — border colors
+- `--code-bg`, `--code-text` — code block colors
+
+### Spacing
+- `--space-1` through `--space-7` — spacing scale
+- Maps to Open Props `--size-N` scale
+
+### Typography
+- `--weight-normal`, `--weight-medium`, `--weight-semibold`, `--weight-bold`
+- `--font-body`, `--font-mono` — font stacks
+- `--line-height-body`, `--line-height-heading`
+- `--width-prose` — max-width for readable text
+
+### Shadows
+- `--shadow-dropdown`, `--shadow-modal` — purpose-named shadows
+
+### Focus / Interaction
+- `--focus-ring-width` — keyboard focus ring width
+
+## Scenarios
+
+### Given a new primitive reference needed
+- **When** a downstream layer needs an Open Props value
+- **Then** add a semantic alias to this file first
+- **And** reference only the alias in the downstream layer
+
+### Given an unused token
+- **When** auditing finds a token alias with zero references in layers 02+
+- **Then** it may be removed from this file
+
+### Given this file
+- **When** inspected
+- **Then** it contains only `:root {}` with `--custom-property: value;` declarations
+- **And** no element selectors, no class selectors, no rules