Bulk token metadata endpoint

[heidar-stacks]

Fetching token (FT and NFT) metadata currently requires one request per token ID, which causes overhead when displaying lists (e.g. in address page > holdings section and tokens table). This results in excessive network calls and potential rate limit.

Proposed solution: adding a new bulk metadata endpoint:

GET /metadata/v1/ft?ids=ID1,ID2,ID3...

potential issue with hitting url max size

POST /metadata/v1/ft
Body: { ids: [ "ID1", "ID2", "ID3" ] }

better in handling larger lists but potential issue with caching

related to: stx-labs/explorer#2544