fix(e2e): respect PLAYWRIGHT_BASE_URL env var and add host.docker.internal resolution

The Playwright config hardcoded localhost:8080 as baseURL, ignoring
the PLAYWRIGHT_BASE_URL env var set in CI. Docker Compose was also
missing extra_hosts to resolve host.docker.internal on Gitea Actions
runners (which use DIND).

Fixes GRO-1496.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/e2e/playwright.config.ts

@@ -19,7 +19,7 @@ export default defineConfig({
   reporter: process.env.CI ? "github" : "list",
 
   use: {
-    baseURL: "http://localhost:8080",
+    baseURL: process.env.PLAYWRIGHT_BASE_URL ?? "http://localhost:8080",
     trace: "on-first-retry",
     screenshot: "only-on-failure",
     serviceWorkers: "block",