fix: call the Gitea API on its public URL (#29)

Release.yml still pointed GITEA_URL at the AWS in-cluster service (gitea-http.gitea.svc.cluster.local), which does not resolve from the Frostmoln runner: every release fails creating the branch with curl exit 6 (e.g. auth0mock run 34722). Use gitea.server_url. Also drop RELEASE_TOKEN_FILE=/runner-secrets/release-token (the AWS runner mount); the Frostmoln runner exports RELEASE_TOKEN_FILE itself.

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https://claude.ai/code/session_01Ma8eHhW59hLAJuLzBnLvUu
Reviewed-on: #29

.gitea/workflows/Release.yml

@@ -14,8 +14,7 @@ concurrency:
   cancel-in-progress: false
 
 env:
-  GITEA_URL: http://gitea-http.gitea.svc.cluster.local:3000
+  GITEA_URL: ${{ gitea.server_url }}
-  RELEASE_TOKEN_FILE: /runner-secrets/release-token
   GIT_CLIFF_VERSION: "2.14.2"
 
 jobs: