docs(send): add meta/argument_specs.yml

29 typed options with full defaults coverage (no required: true marks —
the role works with an empty S3 config when storage_backend=local).
Documents the send_domains list convention, the local-vs-s3 storage
choice, the timing/size limits and the Traefik / network wiring.

Loads through ansible-core's ArgumentSpecValidator. Matches the spec
convention used by the other roles in this collection.

roles/send/meta/argument_specs.yml

@@ -0,0 +1,122 @@
+---
+argument_specs:
+  main:
+    short_description: Deploy timvisee/send (file-sharing) with a Redis backend via Docker Compose.
+    description:
+      - Renders a Compose stack with the C(timvisee/send) container and a
+        Redis companion behind Traefik. Storage can be local-disk or any
+        S3-compatible backend (e.g. the C(garage) role).
+      - Uses the shared C(*_domains) list convention so the router can
+        accept internal C(*.int.*) hostnames alongside the canonical
+        BASE_URL host.
+    options:
+      docker_compose_base_dir:
+        type: path
+        default: /etc/docker/compose
+      docker_volume_base_dir:
+        type: path
+        default: /srv/data
+      send_service_name:
+        type: str
+        default: send
+      send_docker_compose_dir:
+        type: path
+      send_docker_volume_dir:
+        type: path
+
+      send_domains:
+        type: list
+        elements: str
+        default: ['send.local.test']
+        description:
+          - FQDNs the router accepts. First entry is the canonical hostname
+            and is used as C(BASE_URL). Further entries cover internal
+            C(*.int.*) names so backend uploads can hit Send without
+            hairpinning via the DMZ.
+      send_image:
+        type: str
+        default: "registry.gitlab.com/timvisee/send:latest"
+      send_port:
+        type: int
+        default: 1443
+      send_extra_hosts:
+        type: list
+        elements: str
+        default: []
+        description: C(extra_hosts) entries injected into the send container (Docker C(host:ip) syntax).
+
+      send_redis_image:
+        type: str
+        default: "redis:7-alpine"
+      send_redis_service_name:
+        type: str
+        default: send-redis
+
+      send_max_file_size:
+        type: int
+        default: 1073741824
+        description: Max upload size in bytes. Default is 1 GiB.
+      send_default_downloads:
+        type: int
+        default: 1
+      send_max_downloads:
+        type: int
+        default: 100
+      send_default_expire_seconds:
+        type: int
+        default: 86400
+        description: Default share lifetime in seconds (24 h).
+      send_max_expire_seconds:
+        type: int
+        default: 604800
+        description: Maximum share lifetime in seconds (7 d).
+      send_max_files_per_archive:
+        type: int
+        default: 64
+      send_download_counts:
+        type: str
+        default: "1,2,3,4,5,20,50,100"
+        description: Comma-separated list of download-count options shown in the UI.
+      send_expire_times_seconds:
+        type: str
+        default: "300,3600,86400,604800"
+        description: Comma-separated list of expire-time options (seconds) shown in the UI.
+
+      send_storage_backend:
+        type: str
+        choices: [local, s3]
+        default: local
+        description:
+          - C(local) keeps uploads in a host volume. C(s3) uses an
+            S3-compatible backend (any of the C(send_s3_*) variables is
+            required when this is set).
+
+      send_s3_endpoint:
+        type: str
+        default: ''
+      send_s3_bucket:
+        type: str
+        default: ''
+      send_s3_region:
+        type: str
+        default: us-east-1
+      send_s3_access_key:
+        type: str
+        default: ''
+      send_s3_secret_key:
+        type: str
+        default: ''
+      send_s3_use_path_style:
+        type: bool
+        default: true
+        description: Required for most non-AWS S3-compatible backends (Garage, MinIO).
+
+      send_traefik_network:
+        type: str
+        default: proxy
+      send_internal_network:
+        type: str
+        default: send_internal
+      send_use_ssl:
+        type: bool
+        default: true