feat: add sdk query examples app

[izmiradami]

Summary

Adds a new sdk-queries example application under apps/ demonstrating how to use the Shelby SDK for common query operations.

Changes

• Add new apps/sdk-queries example
• Demonstrate SDK query patterns
• Follow repository structure and conventions
• Pass typecheck and lint checks

Validation

• ✅ Typecheck passed
• ✅ Lint passed
• ✅ Formatting verified

Notes

This PR implements the requested migration of the SDK query example into the apps/ directory.

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Note

Low Risk
Documentation and local example scripts only; no changes to shared libraries or production services, though delete-blob can mutate on-chain state when users run it with a private key.

Overview
Adds apps/sdk-queries (@shelby-protocol/query-example) as a set of small tsx scripts that show how to query Shelby via @shelby-protocol/sdk ^0.3.1 on Shelbynet (API key + account address in .env).

Coverage includes account blobs and metadata, blob/activity counts and lists (Hasura-style where), total stored size, placement group slots, and storage providers—each exposed as a pnpm query:* script. delete-blob is the only write path: it signs deleteBlob with SHELBY_ACCOUNT_PRIVATE_KEY.

The root README applications table is updated to link the new app; pnpm-lock picks up the new workspace package.

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