feat: allow conditional revalidation for QUERY requests

[Cherry]

req.fresh only performed weak freshness validation for GET and HEAD, so responses to QUERY requests never returned 304 Not Modified even when the client sent a matching If-None-Match. This extends the method guard to include QUERY.

-  // GET or HEAD for weak freshness validation only
-  if ('GET' !== method && 'HEAD' !== method) return false;
+  // GET, HEAD, or QUERY for weak freshness validation only
+  if ('GET' !== method && 'HEAD' !== method && 'QUERY' !== method) return false;

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As far as I can tell, QUERY is a safe, idempotent, cacheable method whose responses explicitly support conditional revalidation, as per https://datatracker.ietf.org/doc/rfc10008/, so it should behave like GET/HEAD here.

I've added tests where it makes sense, and would also be happy to backport this to v4.x if accepted.

Fixes #7365

[krzysdz]

cc @jonchurch (initial work on QUERY support) @blakeembrey (fresh captain)