[feature]: Add queries for listing asset IDs by group and fetching metadata for any asset ID

[ffranr]

Currently, we can fetch asset metadata by genesis asset ID:

taproot-assets/tapdb/addrs.go

Lines 228 to 230 in e3690c5

	// FetchAssetMetaForAsset fetches the asset meta for a given asset.
	FetchAssetMetaForAsset(ctx context.Context,
	assetID []byte) (AssetMeta, error)

For the supply commitment feature, we need two separate queries for better flexibility:

1. List asset IDs in a group

   • Return all asset IDs (minted tranches) for a given asset group.
   • Order by mint block height.
   • Output format could be a map of block height → asset ID.

2. Fetch metadata for any asset ID

   • Support retrieving asset metadata for any tranche within an asset group, not just the genesis asset.

This would also allow fetching the latest supply commitment delegation key if needed later.

[ffranr]

This might be a useful starting point: #1591