Phase 3: cost-vs-revenue dashboard

ArcadiaCloud.Analytics — the operator margin view. Revenue (tenant
invoices, ex-GST) vs COGS (DO cost lines), margin = revenue - COGS.

- margin_summary/1 — overall P&L + per-tenant + per-deployment margin
  for a month.
- by_kind/1 — revenue and COGS broken down by resource kind (separate
  axes; billing kinds and DO kinds don't 1:1).
- live_accrual/0 — current-month unbilled: runs the quote engine with
  partial metered usage per active subscription. "What tenants are
  racking up right now before the rollup."

COGS-to-tenant attribution uses COALESCE(deployment.tenant_id,
resource.tenant_id) — a resource in a deployment bills to the
deployment's tenant; standalone resources fall back to their own
tenant_id (skyai-internal infra).

API (platform_admin only):
- GET /api/v1/dashboard/margin?period=YYYY-MM-DD
- GET /api/v1/dashboard/accrual

Schema fix: cloud_resources.tenant_id and cloud_projects.tenant_id were
binary_id (UUID) while cloud_deployments / tenant_invoices use string.
Migrated both to text — a UUID is a valid string, arcadia also uses
non-UUID tenant slugs ("platform-admin"), and the type alignment lets
the analytics COALESCE join work. Side benefit: kills the phase-1 bug
where a non-UUID tenant_id claim crashed the inventory query.

Smoke verified against real ingested April DO COGS: pilot deployment on
Studio with 5 droplets, metered + rolled up — by_tenant shows
dashboard-pilot rev $71.12 / COGS $30.53 / margin $40.59 (57.1%);
overall P&L revenue $71.12 vs all-April COGS $86.92 = -$15.80 (the
pilot's revenue doesn't cover Sky AI's full April infra — correct, the
rest is internal/unattributed).

Phase 3 complete: catalog, deployments+subscriptions, quote engine,
metering, invoice rollup, cost-vs-revenue dashboard.

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

lib/arcadia_cloud/cloud/cloud_resource.ex

@@ -13,7 +13,7 @@ defmodule ArcadiaCloud.Cloud.CloudResource do
     field :region, :string
     field :status, :string
     field :size_slug, :string
-    field :tenant_id, :binary_id
+    field :tenant_id, :string
     field :deployment_id, :binary_id
     field :tags, {:array, :string}, default: []
     field :attrs, :map, default: %{}