fix: Update S3 config and add Gitea URL settings

- Change MINIO_ENDPOINT from IP to Docker hostname (s3storage)
- Add ROOT_URL and DOMAIN settings for proper Gitea configuration
- Give anonymous users Admin permission for bucket creation
- Document SeaweedFS bucket creation process

s3_config.json.template

@@ -1,10 +1,13 @@
 {
-  "_comment": "Template file - use 'op inject' to generate s3_config.json",
   "identities": [
     {
       "name": "anonymous",
       "actions": [
-        "Read"
+        "Admin",
+        "Read",
+        "List",
+        "Write",
+        "Tagging"
       ]
     },
     {