Register Asset

Add an artifact to design-assets.json and refresh the visual overview at assets.html.

Argument parsing

From $ARGUMENTS:

Positional 0: html-path (required)
--asset "<name>": display name (default: derive from filename, Title Cased)
--group <X>: one of Type, Colors, Spacing, Components, Brand (default: Components)
--subtitle "<text>": short description
--status <X>: needs-review | approved | changes-requested (default: needs-review)
--auto: silent mode called by /done — skip thumbnail capture (reuses .claude/last-preview.png), don't print confirmation prompts, one-line report only

Capture thumbnail:
- If --auto and .claude/last-preview.png exists: Bash(cp .claude/last-preview.png assets/thumbs/<slug>-<ts>.png) — reuse
- Otherwise: /preview <html-path> → wait 500ms → mcp__chrome-devtools__take_screenshot → save to assets/thumbs/<slug>-<ts>.png (Bash(mkdir -p assets/thumbs) first)