[codex] Retire AutoDoc and generated docs

[YKDZ]

Summary

Retires the AutoDoc system and generated documentation surfaces from the repository.

• removes the AutoDoc tool package, generated docs, semantic fragments, subject manifests, and old AutoDoc skills
• replaces generated docs entry points with hand-written developer docs organized by system topic
• removes tracked Claude-specific agent guidance and keeps agent-local files ignored
• removes bilingual @zh / @en TSDoc tags from active retained assets
• adds repository audit specs for AutoDoc, .claude, developer docs, and bilingual-comment cleanup
• keeps schema generation and moon project sync validation active after the migration

Validation

Local validation before push:

• pnpm vitest run --project unit-root scripts/repository-metadata.spec.ts scripts/agent-surface.spec.ts scripts/bilingual-comments.spec.ts scripts/developer-docs.spec.ts
• moon run docs:typecheck docs:build --quiet
• moon run root:codegen-check --quiet
• moon ci :test :lint :typecheck :fmt --quiet
• moon exec :test :lint :typecheck :fmt --on-failure continue --upstream deep --quiet

Local Playwright E2E was attempted, but the local runner could not reach Docker-published PostgreSQL/Redis ports even though the compose containers were healthy. GitHub CI is expected to provide the authoritative E2E environment.