docs: add security, business, and contribution documentation

docs: add integration and deployment guides

docs: add frontend and smart contract documentation

docs: add API reference and error documentation

docs: add architecture and audit engine documentation

docs: add docs index and getting started guides

feat: add ERC-721 audit certificate contract and Hardhat tooling

feat: build private and public audit report pages

feat: build new audit flow and progress tracking UI

feat: build landing page and pricing experience

feat: build dashboard and audit history experience

feat: add shared UI primitives and global navigation components

feat: add frontend API, auth, validation, and web3 utilities

feat: scaffold Next.js frontend shell and build configuration

test: add backend unit tests for scoring, auth, reports, and payments