add demoGroups metadata, filter demo view wrappers in wcctools, and update demo payloads
- Add public static demoGroups to many web components to enable sidebar categorization in the wcctools dashboard (groups like Dashboard, Dashboard Grids, Network, Services, Platform, Auth & Settings).
- Filter out demo-view wrapper components from the wcctools elements list (html/index.ts) so full-page demo orchestration wrappers are not shown as regular elements.
- Adjust demo/example payload shapes for sz-status-grid-network and sz-status-grid-services (renamed and flattened traffic/status and resource usage properties for the demo fixtures).
- Add readme.hints.md with project structure, web component patterns, demo groups and build/watch instructions.