fix: chown named volumes so the non-root filerun user can install on first run

The filerun/filerun image runs as user filerun (1001:1001), but /var/www/html
is created as root in the image, so the named volume inherits root:root
ownership. The entrypoint's first-run installer then fails to download
filerun.zip into /var/www/html (Permission denied) and the container
crash-loops with exit 1.

- Add a busybox init service that chowns the html and user-files volumes to
  1001:1001 before filerun starts (gated via service_completed_successfully).
- Drop the user: "99:100" override, which is meant for pre-chowned host bind
  mounts in the upstream example, not named volumes.
- Remove the UTF-8 BOM at the start of the file, the legacy links: entry and
  the obsolete version: key.

Verified on a live Dokploy deploy: HTTP 200 with page title
"FileRun :: Installation".

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

blueprints/filerun/docker-compose.yml

@@ -1,14 +1,20 @@
-version: "3.8"
-
 services:
+  filerun-init:
+    image: busybox:1.37
+    restart: "no"
+    command: chown -R 1001:1001 /var/www/html /user-files
+    volumes:
+      - filerun-html:/var/www/html
+      - filerun-user-files:/user-files
+
   filerun:
     image: filerun/filerun:latest
     restart: unless-stopped
-    user: "99:100"
     depends_on:
-      - db
-    links:
-      - db:db
+      filerun-init:
+        condition: service_completed_successfully
+      db:
+        condition: service_started
     environment:
       FR_DB_HOST: db
       FR_DB_PORT: 3306