`validateWebsiteURL` only checked that the URL parses, is absolute, and
uses the `https` scheme. It accepted literal `"`, `'`, `<`, `>`, and
ASCII space — none of which are valid in a URI per RFC 3986, and all of
which broke rendering when the value flowed into the catalogue UI's
`<a href="...">` template.
Add a `strings.IndexAny` check after the scheme check that rejects any
of these characters with a clear `website-url-invalid-characters` issue
that points at the offending byte position. Control characters (`\t`,
`\n`, `\r`) are also covered: they're caught one step earlier by Go's
`url.Parse`, but the bytes are listed in the rejection set so the
behaviour is explicit and survives any future relaxation of `url.Parse`.
Already-percent-encoded URLs (e.g. `?q=hello%20world`) continue to
validate cleanly.
Adds table-driven cases for `"`, `'`, `<>`, space, newline, and a
positive case for percent-encoded special characters.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>