feat: add daily request limit and refactor access control (#759)

- Add daily request limit per IP in blacklist settings (1-1,000,000/day)
- Refactor access control logic: merge blacklist and rate limit checks
- Remove RATE_LIMIT_API_DAILY_REQUESTS env var, use database config instead
- Move x-custom-auth check earlier in middleware chain
- Add comprehensive English documentation (31 new guide pages)
- Improve code structure and error handling

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Co-authored-by: Claude <noreply@anthropic.com>

vitepress-docs/docs/en/guide/email-routing.md

@@ -0,0 +1,9 @@
+# Cloudflare Email Routing
+
+1. In the CF console for the corresponding domain under `Email Routing`, configure the `Email DNS records`. If there are multiple domains, you need to configure `Email DNS records` for each domain.
+
+2. Before binding an email address to your Worker, you need to enable email routing and have at least one verified email address (destination address).
+
+3. Configure the `Catch-all address` in the routing rules of each domain's `Email Routing` to send to `worker`.
+
+![email](/readme_assets/email.png)