fix: use real MagicDNS hostname in serve.headscale.json (focalboard.damconsulting.net)

The {{service}}.yourdomain.com placeholder does not work in tailscale serve -
JSON values are not template-substituted. Use the actual MagicDNS base
domain so the user has a working starting point, matching the pattern
established in ts-homepage.

README.md

@@ -36,7 +36,7 @@ If you're using Headscale instead of Tailscale:
    ```bash
    cp tailscale/config/serve.headscale.json tailscale/config/serve.json
    ```
-4. Edit `serve.json` and replace `{{service}}.yourdomain.com` with your actual domain
+4. Edit `serve.json` to use your actual domain. The default in this file uses `focalboard.damconsulting.net` (Kevin Headscale base domain) - replace it with your own if your setup differs.
 5. Start the stack:
    ```bash
    docker compose up -d

tailscale/config/serve.headscale.json

@@ -5,7 +5,7 @@
     }
   },
   "Web": {
-    "{{service}}.yourdomain.com:80": {
+    "focalboard.damconsulting.net:80": {
       "Handlers": {
         "/": {
           "Proxy": "http://127.0.0.1:8000"
@@ -14,4 +14,3 @@
     }
   }
 }
-