chore: configure local webnovel workflow

[Asterion26]

Summary

• add a local webnovel setup guide for the AI-assisted Chinese webnovel workflow
• add default anti-AI-flavor style profile/rules and strengthen chapter writer defaults
• fix local Vite proxy host and Node test access to Vite env constants

Verification

• pnpm typecheck
• pnpm build
• node --experimental-strip-types --test client/src/lib/constants.test.mjs
• local dev health checks: /api/health via backend and Vite proxy

Note: full repository test suites still have pre-existing unrelated failures; see local run output.