Folding `nfc` into a `static` render suite needs a dispatch mechanism

The TF discussion on #54 converged on three broad suites: static (pre-baked artifacts), data (card object), and html. The spec currently keeps nfc as its own renderSuite value instead of folding it into static, because of a gap:

The nfc suite value tells the wallet what to do with the payload -- transmit it over an NFC radio, not display it. If NFC payloads, images, and PDFs all share renderSuite: "static", nothing else in the render method carries that distinction:

1. template.mediaType does not work: the NFC example uses application/octet-stream, and there is no well-known registered media type that means "NDEF/NFC payload".
2. outputPreference.accessMode (visual, auditory, tactile, textual) describes how a human perceives the rendering, not a machine transmission channel.

Some options include:

• Keep nfc (and similar channel-specific methods) as their own suite values, reserving static for artifacts the wallet displays directly (current state of the spec).
• Fold them into static and add a discriminator property (e.g. a channel or delivery hint).
• Fold them into static and mint/register a dedicated media type for NFC payloads.

Start with the specification's renderSuite definition and trace how template.mediaType and outputPreference.accessMode are used for dispatch. Compare the three options described here and determine which mechanism the specification should adopt; done means the suite model and its NFC distinction are resolved and reflected consistently in the spec.