Add Fluidd runout sensor panel replacement via bookmarklet

CFSync now generates a bookmarklet (footer "Fluidd panel" link) that,
when clicked in Fluidd, replaces the Runout Sensors card with a live
CFS slot grid pulled from CFSync's /api/ui/state API.

- static/fluidd-panel.js: self-contained IIFE; finds Vuetify card by
  title text (Runout Sensors / Filament Sensor), replaces content with
  colour-coded slot grid; falls back to floating panel after 15 s;
  polls every 3 s; handles both Vuetify v2 and v3 DOM structures
- static/app.js: initFluiddBookmarklet() generates javascript: href
  with CFSYNC_URL embedded from window.location.origin; copy button
  fallback via navigator.clipboard
- static/index.html: footer bookmarklet link + copy button
- static/style.css: footer link / copy button styles

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>