Phase 0 scaffold: arcadia-cloud Phoenix service

API-only Phoenix 1.8 project for cloud-ops, inventory, billing, and
provisioning sagas. Validates arcadia JWTs via shared Guardian secret
(verify-only; arcadia-app remains the issuer).

Deps beyond default Phoenix: guardian, cors_plug, oban, req.
Postgres on local port 5433 per arcadia stack convention.
Endpoint runs on :4005.

Endpoints:
- GET /api/health         — public, returns service identifier
- GET /api/v1/inventory   — auth-gated, returns empty list (phase 0 stub)

Oban configured with the queues phase 1+ will need:
provisioning / cloud_sync_fast|full|slow / cloud_billing / metering.

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

config/config.exs

@@ -0,0 +1,55 @@
+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Config module.
+#
+# This configuration file is loaded before any dependency and
+# is restricted to this project.
+
+# General application configuration
+import Config
+
+config :arcadia_cloud,
+  ecto_repos: [ArcadiaCloud.Repo],
+  generators: [timestamp_type: :utc_datetime, binary_id: true]
+
+# Configure the endpoint
+config :arcadia_cloud, ArcadiaCloudWeb.Endpoint,
+  url: [host: "localhost"],
+  adapter: Bandit.PhoenixAdapter,
+  render_errors: [
+    formats: [json: ArcadiaCloudWeb.ErrorJSON],
+    layout: false
+  ],
+  pubsub_server: ArcadiaCloud.PubSub,
+  live_view: [signing_salt: "4W6q5pDB"]
+
+# Configure Elixir's Logger
+config :logger, :default_formatter,
+  format: "$time $metadata[$level] $message\n",
+  metadata: [:request_id]
+
+# Use Jason for JSON parsing in Phoenix
+config :phoenix, :json_library, Jason
+
+# Guardian — JWTs are issued by arcadia-app. arcadia-cloud only verifies them.
+# Issuer and secret_key MUST match arcadia-app's Arcadia.Guardian config.
+config :arcadia_cloud, ArcadiaCloud.Guardian,
+  issuer: "arcadia",
+  verify_issuer: true
+
+# Oban — provisioning, sync, billing, gateway-event consumption queues
+config :arcadia_cloud, Oban,
+  engine: Oban.Engines.Basic,
+  queues: [
+    provisioning: 5,
+    cloud_sync_fast: 5,
+    cloud_sync_full: 3,
+    cloud_sync_slow: 1,
+    cloud_billing: 1,
+    metering: 2,
+    default: 5
+  ],
+  repo: ArcadiaCloud.Repo
+
+# Import environment specific config. This must remain at the bottom
+# of this file so it overrides the configuration defined above.
+import_config "#{config_env()}.exs"