Release & document ThinkSpools (Spoolman + OpenSpoolman)

Released and documented ThinkSpools: filament spool inventory tracking (Spoolman) plus a touchscreen-friendly companion with QR-code scanning and live Bambu Lab printer integration (OpenSpoolman). Covers getting started, FAQ, architecture (two-app QR-redirect + MQTT flow), and why this pairing was chosen over SimplyPrint, Bambuddy, Spool Buddy, FilaMan, Spoolio, and spreadsheet tracking.