waha Dashboard fails to load when served behind Nginx subpath

Describe the bug

Waha is currently running at my public URL, https://www.mydomain.com/waha, and the main interface works. But when I click the dashboard link, it redirects to https://www.mydomain.com/dashboard instead of https://www.mydomain.com/waha/dashboard.

I tried a workaround by configuring Nginx to rewrite and force the URL to https://www.mydomain.com/waha/dashboard. That part works (the redirect goes to the right place), but the dashboard itself never loads — it gets stuck on the "fetching resources" screen.

Version

{
  "version":"2025.8.1",
  "engine":"GOWS",
  "tier":"CORE",
  "browser":null
}

Steps to Reproduce

Run WAHA behind a reverse proxy, under a subpath (e.g. /waha/)
Access WAHA at https://www.mydomain.com/waha/ (this works fine)
Click the dashboard link → it incorrectly redirects to /dashboard instead of /waha/dashboard
Even when forcing the redirect to /waha/dashboard with Nginx, the dashboard page never finishes loading (stuck at fetching resources).

Expected Behavior

WAHA should respect the subpath and correctly load the dashboard at: https://www.mydomain.com/waha/dashboard

Actual Behavior

Default behavior → WAHA redirects to /dashboard (ignores subpath).
Workaround via Nginx rewrite → Redirects correctly to /waha/dashboard, but dashboard still fails to load (resources return with wrong MIME type, CSS/JS not applied).

Additional Context

At the moment WAHA doesn’t seem to support configuring a custom basePath or baseUrl. Other tools (like n8n) handle this by exposing an environment variable (e.g. N8N_PATH or N8N_EDITOR_BASE_URL) that lets you define the public base path. That kind of option would likely solve this issue for setups behind reverse proxies on a subpath.