Frontend: Replace inline SpoolInfoCard/UnknownTagCard with full-screen
TagDetectedModal that auto-opens on NFC tag detection. Known spools show
remaining weight, fill bar, and offer "Assign to AMS" (new sub-modal with
printer selector + AMS slot grid) and "Sync Weight". Unknown tags offer
"Add to Inventory" and "Link to Spool". Modal stays open on tag removal,
won't re-open for dismissed tags, reopens on re-place after removal.
Daemon: Fix PN5180 NFC reader silently stopping tag detection when the
reader drifts into a stuck state. Add auto-recovery (full hardware reset
after 10 consecutive errors), preventive RF cycling every 60s when idle,
and periodic status logging. Heartbeat now reports actual nfc_ok/scale_ok
from reader instances instead of hardcoded True.