Phase 3: deployment model + subscriptions

cloud_deployments — the billable unit (one app instance). A tenant has
1..N deployments; cloud_resources.deployment_id ties resources to one.
Fields: tenant_id, slug (unique per tenant), display_name, region,
state, llm_mode, billing_action_suspended (operator override),
template_code/version (nullable — formal templates land in phase 4).

Lifecycle state machine in ArcadiaCloud.Deployments — states trial /
active / past_due / paused / suspended / cancelled / archived. Every
transition is validated against an explicit @transitions map and
recorded in cloud_deployment_events. create_deployment defaults to
`active` (trial is wired but no flow enters it yet).

subscriptions — one per deployment, binds it to a plan_version. status
active/paused/cancelled, current period dates, trial_ends_at.

subscription_addons — addons attached to a subscription with price + qty
SNAPSHOTTED at attach time, so a later catalog price change can't
retroactively reprice an existing subscriber.

ArcadiaCloud.Subscriptions context: create_subscription (period defaults
to current calendar month), attach_addon (snapshots from the live Addon),
change_plan_version (migrate to a new version — price changes / up-down
grades), get_subscription_for_deployment.

API (platform_admin sees all tenants; others scoped to own tenant_id):
- GET/POST /api/v1/deployments
- GET      /api/v1/deployments/:id            (with subscription + events)
- POST     /api/v1/deployments/:id/transition
- POST     /api/v1/deployments/:id/subscribe  (plan_code + optional addons)

Smoke verified: created a deployment, transitioned active->paused
(events logged with actor), rejected an invalid paused->archived
transition (422), subscribed to Studio with the storage_50gb addon —
addon price snapshotted at 750c/qty 50; show returns deployment +
subscription + event history.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

priv/repo/migrations/20260520150000_create_deployments.exs

@@ -0,0 +1,88 @@
+defmodule ArcadiaCloud.Repo.Migrations.CreateDeployments do
+  use Ecto.Migration
+
+  def change do
+    # A deployment is the billable unit — one app instance. A tenant has
+    # 1..N deployments; resources tag to a deployment via
+    # cloud_resources.deployment_id (already migrated).
+    create table(:cloud_deployments, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :tenant_id, :string, null: false
+      add :cloud_project_id, references(:cloud_projects, type: :binary_id, on_delete: :nilify_all)
+      add :slug, :string, null: false
+      add :display_name, :string
+      # template_code/version nullable — phase 3 pilot deployments are
+      # provisioned by hand; formal templates land in phase 4.
+      add :template_code, :string
+      add :template_version, :string
+      add :region, :string
+      add :state, :string, null: false, default: "active"
+      add :state_since, :utc_datetime, null: false
+      add :llm_mode, :string, null: false, default: "none"
+      # operator override: keep this deployment running even when billing
+      # rules would otherwise suspend it.
+      add :billing_action_suspended, :boolean, null: false, default: false
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create unique_index(:cloud_deployments, [:tenant_id, :slug])
+    create index(:cloud_deployments, [:tenant_id])
+    create index(:cloud_deployments, [:state])
+
+    create table(:cloud_deployment_events, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :deployment_id,
+        references(:cloud_deployments, type: :binary_id, on_delete: :delete_all),
+        null: false
+      add :from_state, :string
+      add :to_state, :string, null: false
+      add :reason, :string
+      add :actor, :string
+      add :notes, :text
+      add :occurred_at, :utc_datetime, null: false
+    end
+
+    create index(:cloud_deployment_events, [:deployment_id, :occurred_at])
+
+    # One subscription per deployment — binds it to a plan version.
+    create table(:subscriptions, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :deployment_id,
+        references(:cloud_deployments, type: :binary_id, on_delete: :delete_all),
+        null: false
+      add :plan_version_id,
+        references(:plan_versions, type: :binary_id, on_delete: :restrict),
+        null: false
+      add :status, :string, null: false, default: "active"
+      add :current_period_start, :date, null: false
+      add :current_period_end, :date, null: false
+      add :trial_ends_at, :date
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create unique_index(:subscriptions, [:deployment_id])
+    create index(:subscriptions, [:plan_version_id])
+    create index(:subscriptions, [:status])
+
+    # Addons attached to a subscription. Price/qty are SNAPSHOTTED at
+    # attach time so later catalog changes don't retroactively reprice.
+    create table(:subscription_addons, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :subscription_id,
+        references(:subscriptions, type: :binary_id, on_delete: :delete_all),
+        null: false
+      add :addon_id, references(:addons, type: :binary_id, on_delete: :restrict), null: false
+      add :resource_kind, :string, null: false
+      add :qty, :decimal, null: false
+      add :price_cents, :integer, null: false
+      add :currency, :string, null: false, default: "AUD"
+      add :attached_at, :utc_datetime, null: false
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create index(:subscription_addons, [:subscription_id])
+  end
+end