migrate to hantim org and consolidate deploy secret name

- Update all references from timothykim/ to hantim/ org
- Rename DEPLOY_KEY to DEPLOY_SSH_KEY everywhere
- Update README to reference org-level secrets

README.md

@@ -23,7 +23,7 @@ On a fresh Rocky Linux 9 (or compatible) install:
 
 ```bash
 dnf install -y git
-git clone https://git.timothykim.net/timothykim/hantim-server.git /opt/hantim
+git clone https://git.timothykim.net/hantim/hantim-server.git /opt/hantim
 bash /opt/hantim/setup.sh
 ```
 
@@ -84,8 +84,9 @@ After running the script:
 Nginx Proxy Manager certs and Let's Encrypt account keys are encrypted with
 git-crypt (see `.gitattributes`). You need the git-crypt key to unlock them.
 
-The following secrets must be configured in the Gitea repo settings for
-deploys to work:
+The following secrets must be configured in the `hantim` Gitea org settings
+(Settings > Actions > Secrets) and are shared across all repos:
 
 - `DEPLOY_HOST` -- the server's IP or hostname
-- `DEPLOY_KEY` -- the SSH private key for the `deploy` user
+- `DEPLOY_SSH_KEY` -- the SSH private key for the `deploy` user
+- `REGISTRY_TOKEN` -- Gitea personal access token for Docker registry login