chore: consolidate Delveworn into a monorepo

[CryptoMickle]

Summary

• import CryptoMickle/rise-dungeon-frontend@781563891a13e4e8ab7b09888b8deed55c2d0da9 as a clean snapshot under frontend/
• keep the Foundry project at the repository root and leave the old frontend repository/history intact
• add path-filtered Contracts CI and Frontend CI workflows
• document the monorepo layout, local setup, deployment configuration, and Practice/onchain trust boundaries

Validation

• forge fmt --check
• forge build
• forge test: 131 passed, 0 failed
• npm --prefix frontend ci
• npm --prefix frontend run lint: 0 errors (15 existing warnings)
• npm --prefix frontend run build
• GitHub Contracts CI: passed
• GitHub Frontend CI: passed

Migration safety

• excluded nested .git and .github metadata
• excluded node_modules, .next, .vercel, local environment files, and oversized files
• checked the imported snapshot for common credential patterns
• did not rename the repository, change Vercel, merge to main, or archive the old frontend repository

Follow-up after review

• rename CryptoMickle/rise-dungeon to CryptoMickle/delveworn
• point the existing Vercel project at this repository with Root Directory frontend
• verify production before archiving the old private frontend repository