Phase 3: pricing catalog

Five catalog tables:
- plans            — plan identity (code, name); the stable thing.
- plan_versions    — versioned pricing (base_price_cents, currency,
                     status draft/active/retired). A subscription binds
                     to a version; raising prices = publish a new
                     version, existing subs unaffected until migrated.
- plan_items       — what a version includes per resource_kind, plus
                     overage terms (overage_unit, overage_price_cents,
                     hard_cap_qty).
- addons           — a la carte upgrades (code, resource_kind, qty,
                     price_cents).
- resource_prices  — effective-dated fallback per-unit pricing for
                     ad-hoc items not covered by a plan.

ArcadiaCloud.Catalog context: plan + version CRUD, active_version/1
(what a new signup gets), publish_version/1 (retires the prior active
version transactionally then activates the new one),
current_resource_price/2 (effective-dated lookup).

Seed (priv/repo/seeds/catalog_seed.exs, idempotent) creates three AUD
plans — Starter $20, Studio $50, Pro $120/mo — with included
droplet_hours / spaces_gb_month / snapshot_gb_month / bandwidth_gb /
dns_zones (and LLM token allowances on Studio + Pro), plus three storage
/ LLM addons. Prices are placeholders to tune against real DO COGS once
the cost-vs-revenue dashboard lands.

API (authenticated tenants — the catalog is what they pick from):
- GET /api/v1/catalog/plans   — plans with active version + items
- GET /api/v1/catalog/addons

Smoke verified: seed creates 3 plans + 3 addons; endpoints return the
shaped catalog.

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

priv/repo/migrations/20260520140000_create_catalog.exs

@@ -0,0 +1,87 @@
+defmodule ArcadiaCloud.Repo.Migrations.CreateCatalog do
+  use Ecto.Migration
+
+  def change do
+    # Plan identity — the stable thing customers refer to ("Studio").
+    create table(:plans, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :code, :string, null: false
+      add :name, :string, null: false
+      add :description, :text
+      add :active, :boolean, null: false, default: true
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create unique_index(:plans, [:code])
+
+    # Versioned pricing. A subscription binds to a specific plan_version;
+    # raising prices = publishing a new version, existing subs unaffected
+    # until explicitly migrated.
+    create table(:plan_versions, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :plan_id, references(:plans, type: :binary_id, on_delete: :delete_all), null: false
+      add :version, :integer, null: false
+      add :base_price_cents, :integer, null: false, default: 0
+      add :currency, :string, null: false, default: "AUD"
+      add :status, :string, null: false, default: "draft"
+      add :published_at, :utc_datetime
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create unique_index(:plan_versions, [:plan_id, :version])
+    create index(:plan_versions, [:status])
+
+    # What a plan version INCLUDES, per resource kind, plus overage terms.
+    create table(:plan_items, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :plan_version_id,
+        references(:plan_versions, type: :binary_id, on_delete: :delete_all),
+        null: false
+      add :resource_kind, :string, null: false
+      add :included_qty, :decimal, null: false, default: 0
+      add :overage_unit, :string
+      add :overage_price_cents, :integer
+      add :hard_cap_qty, :decimal
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create unique_index(:plan_items, [:plan_version_id, :resource_kind])
+
+    # A la carte upgrades. Not versioned for MVP — price changes apply
+    # forward; existing subscription addon refs keep the price snapshotted
+    # on the subscription (phase 3 subscriptions chunk).
+    create table(:addons, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :code, :string, null: false
+      add :name, :string, null: false
+      add :resource_kind, :string, null: false
+      add :qty, :decimal, null: false, default: 0
+      add :price_cents, :integer, null: false, default: 0
+      add :currency, :string, null: false, default: "AUD"
+      add :active, :boolean, null: false, default: true
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create unique_index(:addons, [:code])
+
+    # Fallback per-unit pricing for ad-hoc / pure-usage items not covered
+    # by a plan_item. Effective-dated.
+    create table(:resource_prices, primary_key: false) do
+      add :id, :binary_id, primary_key: true
+      add :resource_kind, :string, null: false
+      add :unit, :string, null: false
+      add :unit_price_cents, :integer, null: false
+      add :currency, :string, null: false, default: "AUD"
+      add :effective_from, :date, null: false
+      add :effective_to, :date
+
+      timestamps(type: :utc_datetime)
+    end
+
+    create index(:resource_prices, [:resource_kind, :effective_from])
+  end
+end