fix(homarr): use named volume for /appdata and hex encryption key

- Replace the relative bind mount `../homarr/appdata:/appdata` with a
  named volume `homarr_appdata:/appdata` so the data survives cleanups
  and can be backed up through Dokploy volume backups.
- Generate SECRET_ENCRYPTION_KEY with `${hash:64}` instead of
  `${password:64}`: homarr requires a 64-character hex string
  (`openssl rand -hex 32`) and the password helper emits non-hex
  characters (g-z).

Closes #738

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

blueprints/homarr/docker-compose.yml

@@ -4,8 +4,11 @@ services:
     restart: unless-stopped
     volumes:
       # - /var/run/docker.sock:/var/run/docker.sock # Optional, only if you want docker integration
-      - ../homarr/appdata:/appdata
+      - homarr_appdata:/appdata
     environment:
       - SECRET_ENCRYPTION_KEY=${SECRET_ENCRYPTION_KEY}
     ports:
       - 7575
+
+volumes:
+  homarr_appdata:

blueprints/homarr/template.toml

@@ -1,6 +1,6 @@
 [variables]
 main_domain = "${domain}"
-secret_key = "${password:64}"
+secret_key = "${hash:64}"
 
 [config]
 env = ["SECRET_ENCRYPTION_KEY=${secret_key}"]