New web UI with iPhone web app

Redesigned status, log, tag generator and settings pages: spool rings in
filament colour, live job card (progress and time left read from CC2
Control's /api/printer while a job runs), log page with filters, iOS-style
settings with a write/dry-run switch. On phones: bottom tab bar, printer
switcher, slot details in a bottom sheet. Dark mode follows the system.
Web app manifest and home screen icons for "Add to Home Screen".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014GcEk5tkfFSYD6NTF66NkC

app/static/icon.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64"><rect width="64" height="64" rx="14" fill="#14181F"/><circle cx="32" cy="32" r="23" fill="none" stroke="#fff" stroke-width="4.5"/><circle cx="32" cy="32" r="12" fill="none" stroke="#6E8BFF" stroke-width="9"/><circle cx="32" cy="32" r="3" fill="#fff"/></svg>