feat(api,ui): complete organization refactor

[markwylde]

Summary

• document organization refactor and org switching specs
• add organization-scoped enterprise schema, backend flows, and audit context
• add admin/user UI organization management plus SDK organization-aware session support
• fix organization-aware OTP/session enforcement and forced OTP UI routing
• align screenshot and Playwright fixtures with explicit organization assignment

Verification

• npm run tidy
• npm run build
• npm run test --workspace @DarkAuth/api -- --runInBand
• COLOR_SCHEME=light npx playwright test tests/api/oidc-auth-edge-cases.spec.ts tests/api/oidc-nonce-code-flow.spec.ts tests/api/password-reset.spec.ts tests/api/user-key-management-delivery.spec.ts tests/api/user-key-management-unlock-journeys.spec.ts tests/api/users-endpoint-auth.spec.ts tests/auth/user-otp-setup-and-verify.spec.ts tests/security/email-verification.spec.ts --workers=1 --retries=0
• COLOR_SCHEME=dark npx playwright test tests/api/oidc-auth-edge-cases.spec.ts tests/api/oidc-nonce-code-flow.spec.ts tests/api/password-reset.spec.ts tests/api/user-key-management-delivery.spec.ts tests/api/user-key-management-unlock-journeys.spec.ts tests/api/users-endpoint-auth.spec.ts tests/auth/user-otp-setup-and-verify.spec.ts tests/security/email-verification.spec.ts --workers=1 --retries=0
• COLOR_SCHEME=light npx playwright test tests/user/auth/login.spec.ts tests/user/auth/password-reset-ui.spec.ts tests/user/dashboard/apps-visible.spec.ts tests/user/dashboard/dashboard.spec.ts tests/user/portal-responsive.spec.ts --workers=1 --retries=0

Notes

• Build emits existing Vite chunk-size and Browserslist freshness warnings.