fix: redirect legacy public template entry to gallery - #3653

Summary

Requests to https://app.teable.ai/public/template currently lead to a missing page. Add a host-scoped Next.js redirect to send that legacy entry point to https://teable.ai/templates with HTTP 301, preserving query parameters.

Use statusCode: 301 explicitly because permanent: true returns 308. The host matcher escapes the dots and the source matches only the entry path, leaving China-cloud and self-hosted domains, template-detail paths, and unrelated routes unaffected.

Validation

• Loaded the edited application config and exercised it with Next.js 16.1.6's unstable_getResponseFromNextConfig on Node.js 22.
• All 10 cases passed: HTTP/HTTPS entry requests, query-string preservation, China-cloud and self-hosted domains, a lookalike hostname, the marketing domain, template-detail paths, a similar path, and login.
• Nonmatching cases were verified to produce no redirect; these config-level checks do not assert the final page status.
• JavaScript syntax, Prettier 3.2.5 with repository formatting options, and git diff --check passed.
• Full monorepo build and test suites were not run for this config-only change.

The redirect becomes live after the application deployment includes this change.