Problem

When doing OAuth from a remote/server setup (SSH into a host, browser on another machine), gog auth add --remote --step 1 generates an auth URL with a fixed redirect URI (http://localhost:1).

In my setup, I expected to use the host's Tailscale FQDN (for example https://molty2.tail8108.ts.net) as callback target, but there appears to be no way to override callback host/redirect URI.

Reproduction

1. On a remote host, run:

   gog auth add user@example.com --services gmail --remote --step 1

2. Observe generated URL includes:
   • redirect_uri=http%3A%2F%2Flocalhost%3A1
3. Check help for gog auth add:
   • It exposes --remote, --step, --auth-url, --manual, but no callback/redirect override flag.

Actual Behavior

• Redirect URI is hard-coded to localhost in remote mode.
• No CLI option to set callback host/port or full redirect URI.

Expected Behavior

One of:

1. Add an explicit override flag (for example --redirect-uri or --callback-url) for auth flows.
2. Add host/port flags (for example --callback-host, --callback-port) and derive redirect URI from those.
3. At least document that remote mode is intentionally localhost-only and why.

Why this matters

Remote/server operators often authenticate from a laptop browser against services running on another machine (Tailscale, SSH, cloud VMs). A configurable callback URL would make auth flow clearer and easier to automate in those environments.

If this is a deliberate design choice, I’m happy to open a docs PR clarifying the intended remote workflow.