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/dev.exs

@@ -0,0 +1,64 @@
+import Config
+
+# Configure your database — uses the shared local Postgres on port 5433
+# (arcadia stack convention; see project_arcadia_local_dev memory).
+config :arcadia_cloud, ArcadiaCloud.Repo,
+  username: "postgres",
+  password: "postgres",
+  hostname: "localhost",
+  port: 5433,
+  database: "arcadia_cloud_dev",
+  stacktrace: true,
+  show_sensitive_data_on_connection_error: true,
+  pool_size: 10
+
+# For development, we disable any cache and enable
+# debugging and code reloading.
+config :arcadia_cloud, ArcadiaCloudWeb.Endpoint,
+  http: [ip: {127, 0, 0, 1}, port: 4005],
+  check_origin: false,
+  code_reloader: true,
+  debug_errors: true,
+  secret_key_base: "FkyzbvuBWWUEnx/M5KDYyEQdPVbxAiFIkNFbSUK+/DCFvRM+W0NGCnE0bGW6NnCk",
+  watchers: []
+
+# Guardian — must match arcadia-app's Arcadia.Guardian dev secret_key
+# (shared verbatim with arcadia-social and arcadia-voice).
+config :arcadia_cloud, ArcadiaCloud.Guardian,
+  secret_key: "DuMkIRN3Qcxk8VqOu8nHj5i7a7a7YgBHF4oXqKwDI4A="
+
+# ## SSL Support
+#
+# In order to use HTTPS in development, a self-signed
+# certificate can be generated by running the following
+# Mix task:
+#
+#     mix phx.gen.cert
+#
+# Run `mix help phx.gen.cert` for more information.
+#
+# The `http:` config above can be replaced with:
+#
+#     https: [
+#       port: 4001,
+#       cipher_suite: :strong,
+#       keyfile: "priv/cert/selfsigned_key.pem",
+#       certfile: "priv/cert/selfsigned.pem"
+#     ],
+#
+# If desired, both `http:` and `https:` keys can be
+# configured to run both http and https servers on
+# different ports.
+
+# Enable dev routes for dashboard and mailbox
+config :arcadia_cloud, dev_routes: true
+
+# Do not include metadata nor timestamps in development logs
+config :logger, :default_formatter, format: "[$level] $message\n"
+
+# Set a higher stacktrace during development. Avoid configuring such
+# in production as building large stacktraces may be expensive.
+config :phoenix, :stacktrace_depth, 20
+
+# Initialize plugs at runtime for faster development compilation
+config :phoenix, :plug_init_mode, :runtime