add local setup doc

README.md

@@ -23,6 +23,37 @@ Create these A records pointing to your VPS IP:
 | `nextcloud.t-gstone.de` | `<VPS_IP>` |
 | `git.t-gstone.de`       | `<VPS_IP>` |
 
+## Local Setup
+
+### SSH Access
+
+Add this to `~/.ssh/config` on your local machine:
+
+```
+Host t-gstone.de
+    HostName t-gstone.de
+    User gstone
+    Port 55
+    IdentityFile ~/.ssh/id_ed25519
+    UseKeychain yes
+    AddKeysToAgent yes
+```
+
+Generate a key and copy it to the VPS:
+
+```bash
+# Generate key (skip if you already have ~/.ssh/id_ed25519)
+ssh-keygen -t ed25519
+
+# Copy it to the VPS (will ask for your password once)
+ssh-copy-id -p 55 gstone@t-gstone.de
+
+# Store passphrase in macOS Keychain
+ssh-add --apple-use-keychain ~/.ssh/id_ed25519
+```
+
+After this, `ssh t-gstone.de` connects without any password prompts.
+
 ## Quick Start
 
 ```bash