chore: use support@wickra.org for contact/author email; drop dead sponsor link (#97)

Now that the wickra.org catch-all mailbox exists, move the project contact +
package-author email off the personal gmail to support@wickra.org across all
surfaces: CODE_OF_CONDUCT, SECURITY, CITATION.cff, Cargo.toml, the npm + PyPI
author fields, the release.yml npm author, and repo-metadata.toml. (The
package-author changes take effect on the next published release.)

repo-metadata.toml's [audit].forbidden still pins kingchencp@gmail.com (the
private commit email) as a banned substring — unchanged.

Also remove the FUNDING.yml custom "https://wickra.org/sponsor" entry: that
page 404s, so the Sponsor button linked to a dead URL. The GitHub Sponsors
entry (github: [kingchenc]) stays.

repo-metadata.toml

@@ -21,7 +21,7 @@ security_url = "https://github.com/wickra-lib/wickra/security/advisories/new"
 # not move with the GitHub org transfer. `github` is the org @-mention slug
 # used in CODEOWNERS and prose.
 handle = "kingchenc"
-email  = "wickra.lib@gmail.com"
+email  = "support@wickra.org"
 github = "wickra-lib"
 
 [badges]