docs(collection): document all roles and fix metadata drift

Replace ansible-galaxy init placeholders across the collection and
correct documentation that drifted from the code, after a multi-agent
review of every role README against its defaults, tasks and templates.

Collection level:
- README: role table for all 16 roles, requirements and role-ordering
- galaxy.yml: declare community.docker and community.general deps,
  real description/tags/urls; normalize license to MIT-0
- meta/runtime.yml: requires_ansible '>=2.15.0'
- plugins/README: document the homarr_layout filter and
  garage_credentials lookup instead of scaffold boilerplate

Per-role meta/main.yml and README for the placeholder roles
(389ds, authentik, authentik_outpost_ldap, base, collabora, drawio,
garage, homarr, httpbin, keycloak, nextcloud, opencloud, traefik).

Correctness fixes found during review:
- keycloak: wrong domain default, drop invented keycloak_cert_resolver,
  document the provisioning feature
- garage: root_domain is .s3.<first-entry>, not the bare domain
- opnform: jwt/front_api secrets use `openssl rand -hex 32`; align the
  validation fail_msg in tasks/main.yml accordingly
- send: S3 example references garage_s3_domains[0] (was singular)
- opencloud: document required opencloud_wopi_domain

License normalized to MIT-0 across galaxy.yml, role meta and READMEs to
match the SPDX headers.

roles/opencloud/README.md

@@ -1,38 +1,43 @@
-Role Name
-=========
+# opencloud
 
-A brief description of the role goes here.
+Deploys [OpenCloud](https://opencloud.eu/) (`opencloudeu/opencloud`) as a
+self-contained file platform via Docker Compose behind Traefik. Supports
+the built-in IdP or external OIDC, optional S3 storage, external LDAP,
+Collabora and draw.io integration, and OIDC-claim-based role assignment.
 
-Requirements
-------------
+## Role variables
 
-Any pre-requisites that may not be covered by Ansible itself or the role should be mentioned here. For instance, if the role uses the EC2 module, it may be a good idea to mention in this section that the boto package is required.
+A selection of the most relevant variables — see
+[defaults/main.yml](defaults/main.yml) for the full set.
 
-Role Variables
---------------
+| Variable | Default | Description |
+| --- | --- | --- |
+| `opencloud_domain` | `opencloud.local.test` | FQDN the Traefik router matches. |
+| `opencloud_image` | `opencloudeu/opencloud:latest` | Container image. |
+| `opencloud_port` | `9200` | Container port Traefik forwards to. |
+| `opencloud_admin_password` | `admin` | Initial admin password — **override this**. |
+| `opencloud_traefik_network` | `proxy` | Docker network shared with Traefik. |
+| `opencloud_use_ssl` | `true` | Enable the TLS resolver on the router. |
+| `opencloud_oidc_issuer` | `""` | External OIDC issuer; empty uses the built-in IdP. |
+| `opencloud_use_s3_storage` | `false` | Use S3 storage instead of local disk. |
+| `opencloud_ldap_uri` | `""` | External LDAP URI; empty uses the built-in directory. |
+| `opencloud_collabora_domain` | `""` | Collabora server domain; set with `opencloud_wopi_domain` to enable editing. |
+| `opencloud_wopi_domain` | `""` | WOPI server FQDN; required alongside `opencloud_collabora_domain`. |
+| `opencloud_drawio_url` | `""` | draw.io URL; set to enable diagram editing. |
+| `opencloud_role_assignment_driver` | `default` | Set to `oidc` to map OIDC claims to roles. |
 
-A description of the settable variables for this role should go here, including any variables that are in defaults/main.yml, vars/main.yml, and any variables that can/should be set via parameters to the role. Any variables that are read from other roles and/or the global scope (ie. hostvars, group vars, etc.) should be mentioned here as well.
+## Example
 
-Dependencies
-------------
+```yaml
+- hosts: services
+  become: true
+  roles:
+    - role: digitalboard.core.opencloud
+      vars:
+        opencloud_domain: "opencloud.example.com"
+        opencloud_admin_password: "{{ vault_opencloud_admin_password }}"
+```
 
-A list of other roles hosted on Galaxy should go here, plus any details in regards to parameters that may need to be set for other roles, or variables that are used from other roles.
+## License
 
-Example Playbook
-----------------
-
-Including an example of how to use your role (for instance, with variables passed in as parameters) is always nice for users too:
-
-    - hosts: servers
-      roles:
-         - { role: username.rolename, x: 42 }
-
-License
--------
-
-BSD
-
-Author Information
-------------------
-
-An optional section for the role authors to include contact information, or a website (HTML is not allowed).
+MIT-0