Add resource: Uniblock

### Resource name

Uniblock

### Short description

Uniblock is a unified API that routes each request across 55+ upstream
providers behind one API key, covering JSON-RPC alongside token, NFT,
market data, and transaction endpoints. Routing and failover score
providers on latency, cost, freshness, and correctness.

### Website URL

https://uniblock.dev/

### LLMs Text URL (optional)

https://docs.uniblock.dev/llms.txt

### Thumbnail image URL (optional)

https://framerusercontent.com/images/nO0jC4V5gHoijj0bepWnCGEFEBg.svg?width=172&height=142

### Banner image URL (optional)

https://pbs.twimg.com/profile_banners/1502365035800182785/1780672635/1500x500

### Twitter / X URL (optional)

https://x.com/Uniblock

### Repository URL(s)

_No response_

### Package URL(s)

_No response_

### Tags (optional)

_No response_

### Subcategory (optional)

_No response_

### Confirmations

- [x] Any tags or subcategory I suggested come from `catalog/taxonomy.json`
- [x] I included at least one of website, repository URL(s), or package URL(s)

Start by inspecting catalog/taxonomy.json and the repository's existing resource entries to find the expected record shape. Add Uniblock using the supplied description and URLs, and verify that the resource is represented consistently; the issue names no test or validation command.

Written by the indexing model from the issue text.