docs: remove TS_LOGIN_SERVER from Tailscale Quick Start (it's the default)

README.md

@@ -12,7 +12,6 @@ This project sets up a Vikunja instance with Tailscale VPN integration using Doc
    ```
 2. Edit `.env` and set:
    - `TS_AUTHKEY` — your Tailscale auth key
-   - `TS_LOGIN_SERVER` — leave as `https://controlplane.tailscale.com` (default)
 3. Start the stack:
    ```bash
    docker compose up -d
@@ -29,7 +28,6 @@ If you're using Headscale instead of Tailscale:
    ```
 2. Edit `.env` and set:
    - `TS_AUTHKEY` — your Headscale auth key
-   - `TS_LOGIN_SERVER` — your Headscale server URL
 3. Switch to the Headscale serve config:
    ```bash
    cp tailscale/config/serve.headscale.json tailscale/config/serve.json