gokapi: headless first-run setup (GOKAPI_USERNAME=admin + generated GOKAPI_PASSWORD)

Gokapi sat in maintenance mode since deploy because /setup was never completed and the
template provided no headless-setup env. GOKAPI_USERNAME/PASSWORD configure it on first
start; password is felhom-generated (deploy field, shown to customer). Fixes share.* maintenance page.

templates/gokapi/.felhom.yml

@@ -32,6 +32,13 @@ deploy_fields:
     locked_after_deploy: true
     description: "Az alkalmazás aldomainje"
 
+  - env_var: GOKAPI_PASSWORD
+    label: "Admin jelszó"
+    type: password
+    generate: "password:24"
+    locked_after_deploy: true
+    description: "A Gokapi admin felhasználó (admin) jelszava — ezzel tudsz belépni a kezelőfelületre"
+
 # --- App info (info page content) ---
 app_info:
   tagline: "Ideiglenes fájlmegosztás lejáró linkekkel"

templates/gokapi/docker-compose.yml

@@ -13,6 +13,11 @@ services:
     restart: unless-stopped
     environment:
       - TZ=Europe/Budapest
+      # Headless first-run setup: GOKAPI_USERNAME/PASSWORD take effect only on the first start (when
+      # Gokapi creates its config). Without these, Gokapi sits in "maintenance mode" until /setup is
+      # completed by hand. Password is felhom-generated (see .felhom.yml deploy field).
+      - GOKAPI_USERNAME=admin
+      - GOKAPI_PASSWORD=${GOKAPI_PASSWORD}
     volumes:
       - gokapi_data:/app/data
       - gokapi_config:/app/config