Prefer native Insert from URL over BE_HTTP_* by default

[fsans]

Summary

• Adds a new Critical Pattern in SKILL.md directing the agent to prefer FileMaker's native Insert from URL script step over the BE_HTTP_* / BE_CurlSetOption plugin functions.
• Rationale: the native step uses the same libcurl library as the BE_HTTP_* functions, requires no plugin, and runs on every client (FMP, FMS, Go, WebDirect).
• Rule (generic, no exclusion list): do not use BE_HTTP_* / BE_CurlSetOption to replace any functionality that the native Insert from URL script step can perform, unless the user explicitly requests the plugin functions.
• Mirrors the same rule as a blockquote at the top of references/http-urls.md so it's visible whenever the HTTP reference is loaded.

Test plan

• Open baseelements-plugin/SKILL.md and verify the new "HTTP — prefer native Insert from URL" pattern reads correctly under Critical Patterns, followed by the existing "HTTP (BE_HTTP_*) — configure before, inspect after" pattern.
• Open baseelements-plugin/references/http-urls.md and verify the blockquote appears above the BE_HTTP_GET section.
• Confirm no other reference files or category table rows were affected.

[nickorr]

There's still some things that the BE functions can do that IFU can't. For example I was using BE HTTP GET to do a HEAD request to a server, combined with the CURLOPT_CERTINFO setting before the request, and then the BE_CurlGetInfo function after. I used that to pull out server certificate expiry info to know when I needed to replace a FMS certificate.

So you may want to consider matching the curl options that BE allows with the ones that IFU does and comparing. ( If you did this and IFU caught up to BE then I'd happily deprecate the BE functions. )

And feel free to send me any PRs for modifications to documentation in the BE repo.

Best of luck with this.

Cheers,
Nick