Fix stale build-guide links, document the implemented quotes API scopes/endpoints, and clarify quote access plus permission-denial behavior so docs match route and test-backed behavior.
- Move API, ARCHITECTURE, BUILD, DEVELOPMENT, and fix docs to docs/ - Move README variants and WINDOWS_BUILD to docs/ - Move assets and screenshots to docs/assets/ - Update GETTING_STARTED, README, CONTRIBUTOR_GUIDE, PROJECT_STRUCTURE, LOCAL_TESTING_WITH_SQLITE, VERSION_MANAGEMENT