fix(ai-image-generation): add missing /shelby base path to blob URL

[Dusk1e]

Summary

NEXT_PUBLIC_SHELBY_API_URL points at the host root, so GeneratedImages builds https://api.shelbynet.shelby.xyz/v1/blobs/.... That path is served by the Aptos fullnode, which has no such route, so every image in the gallery 404s. The blob service is mounted under /shelby, which the app's own upload hook and the README already use.

Tests

curl https://api.shelbynet.shelby.xyz/v1/blobs/<account>/test.png returns {"message":"not found","error_code":"web_framework_error","vm_error_code":null}, the fullnode's router 404.

curl https://api.shelbynet.shelby.xyz/shelby/v1/blobs/<account>/test.png returns {"error":"Blob not found","message":"Blob test.png does not exist for account 0x1"}, so the route resolves and the account and blob name are parsed.

With the corrected value, the URL the gallery builds is identical to the one useUploadImageToShelby.tsx already returns after an upload.

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Note

Low Risk
Single-line example env change only; no runtime code changes, but correct local .env values are required for images to load.

Overview
Updates NEXT_PUBLIC_SHELBY_API_URL in .env.example from the API host root to https://api.shelbynet.shelby.xyz/shelby.

The gallery builds image URLs as {NEXT_PUBLIC_SHELBY_API_URL}/v1/blobs/.... Without the /shelby prefix, those requests hit the Aptos fullnode (which has no blob route) and 404; with it, they match the blob service path already used in the README and upload flow.

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