Support up to 5 colors on OpenSpool tags

[RrrrobertB1992]

OpenSpool Extended tags can now carry up to 4 extra colors alongside the primary color, written as additional_color_hexes. When a tag is read, its extra colors load back into colors 2-5.

• Each extra color has its own checkbox and must be enabled before it can be set. Only enabled colors are written.
• The next color's checkbox appears once the previous one is enabled. Disabling a color also disables the ones after it, so colors stay in order.
• The extra colors moved from the Advanced section to sit under Color 1.
• OpenPrintTag keeps colors 2-4 with the same per-color checkboxes. OpenSpool Compat does not write extra colors.

Related PRs

Together these let multi-color OpenSpool tags made here show all their colors on a Snapmaker U1 running the paxx12 Extended Firmware:

• OpenSpool: parse additional_color_hexes for multicolor spools suchmememanyskill/OpenRFID#37: OpenRFID parses additional_color_hexes from OpenSpool tags.
• OpenRFID: forward additional filament colors to filament_detect paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#788: the firmware forwards colors 2-5 from OpenRFID to filament_detect.

Testing

• Tested with a real NFC tag. Started with 1 color, then added 1 color at a time up to 5. Every combination wrote and read back correctly, and the tag JSON was correct per the OpenSpool spec.
• Enabled all colors with a different color in each, then disabled color 2. Only color 1 was written to the tag, as expected.
• Also checked in a headless browser: checkbox order, the written additional_color_hexes array, tags with more than 4 extra colors being cut to 4, OpenSpool Compat leaving extras off, and OpenPrintTag colors 2-4 writing and reading back. No console errors.

Made with help from Claude