feat: expose AuxSection UUIDs (instanceUuid, packageUuid) from ICode SLIX2 tags

[gienne]

Feature request

When reading an ICode SLIX2 tag (ISO 15693) written by Prusa (Prusament spools), the NFC agent correctly decodes the main NDEF record and returns fields like materialName, brandName, nominalWeight, etc.

However, the AuxSection of the tag (OpenPrintTag key-value pairs) contains critical identifiers that are not currently exposed:

Key	Field	Example
0	consumedWeight	0
1	instanceUuid	24f63c0b-c3d6-5b34-9c94-3eb30c0c3cb9
2	packageUuid	d739306a-d829-5ecc-b634-9034bb20a6cd
3	materialUuid	32990aa5-22b8-5762-90b5-ef27f80e0705
4	brandUuid	ae5ff34e-298e-50c9-8f77-92a97fb30b09

These UUIDs are visible in the Prusa app but absent from the /v1/readers/{index}/card response.

Expected behaviour

The card response should include these UUIDs alongside the existing decoded fields:

{
  "uid": "05b80866080104e0",
  "data": {
    "materialName": "ASA Signal White",
    "instanceUuid": "24f63c0b-c3d6-5b34-9c94-3eb30c0c3cb9",
    "packageUuid":  "d739306a-d829-5ecc-b634-9034bb20a6cd",
    "materialUuid": "32990aa5-22b8-5762-90b5-ef27f80e0705",
    "brandUuid":    "ae5ff34e-298e-50c9-8f77-92a97fb30b09",
    "nominalWeight": 800,
    ...
  }
}

Why this matters

Without packageUuid, inventory apps cannot automatically link a scanned spool to its entry in the OpenPrintTag community catalogue. A fallback search by brand + material type + colour name is possible but imprecise — identical colour names across product lines can return wrong results.

With packageUuid exposed, a single exact lookup in the catalogue database is possible.

Context

• Tag type: ICode SLIX2 (ISO 15693), 320 bytes
• Tested with: Prusament ASA Signal White factory tag
• UUIDs confirmed present on tag (verified via Prusa app)
• nfc-agent fork used: gienne/nfc-agent (includes PR Fix: MaterialType enum values to match OpenPrintTag specification #5 fixes)