Give the dev stack a broker, a time-series database, and live backend source

The mqtt and influx node types had nothing to talk to locally; mosquitto and
influxdb fill that in, on the compose network only — no host port, since 1883
usually belongs to a real broker on the machine.

The same file's --reload only ever reloaded the source baked into the image:
develop.watch needs `docker compose watch`, and the dev stack starts detached.
A bind mount is what the standard flow actually reads.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H7LwYgJfpkbLCTeiAf8U4A

docker/compose.dev.yml

@@ -48,10 +48,44 @@ services:
   redis:
     restart: "no"
 
+  # A broker and a time-series database of the stack's own, so the mqtt and
+  # influx node types are testable without external hardware. Point a node at
+  # broker_host `mosquitto` or url `http://influxdb:8086`.
+  #
+  # Neither publishes a host port on purpose: nothing outside the stack needs
+  # them, and 1883 in particular tends to be taken by the real broker on a
+  # machine that runs this alongside anything else.
+  mosquitto:
+    image: eclipse-mosquitto:2
+    restart: "no"
+    # The config the image ships for exactly this: listener on 1883, anonymous
+    # clients allowed. Its default config accepts neither.
+    command: mosquitto -c /mosquitto-no-auth.conf
+
+  influxdb:
+    image: influxdb:2.7
+    restart: "no"
+    # Dev credentials, and no volume: the container comes up initialised and a
+    # `down -v` is all it takes to start over.
+    environment:
+      DOCKER_INFLUXDB_INIT_MODE: setup
+      DOCKER_INFLUXDB_INIT_USERNAME: fluksio
+      DOCKER_INFLUXDB_INIT_PASSWORD: fluksio-dev-password
+      DOCKER_INFLUXDB_INIT_ORG: fluksio
+      DOCKER_INFLUXDB_INIT_BUCKET: fluksio
+      DOCKER_INFLUXDB_INIT_ADMIN_TOKEN: fluksio-dev-token
+
   backend:
     restart: "no"
     ports:
       - "8000:8000"
+    # Not a startup requirement — listed so the two come up with the stack,
+    # which starts its services by name (`make dev-local`).
+    depends_on:
+      mosquitto:
+        condition: service_started
+      influxdb:
+        condition: service_started
     build:
       context: ..
       dockerfile: backend/Dockerfile
@@ -72,6 +106,11 @@ services:
           action: rebuild
     volumes:
       - ../backend/htmlcov:/app/backend/htmlcov
+      # What makes --reload above mean anything in the detached flow (`make dev`,
+      # `make dev-local`): it starts the stack with `up -d`, which never runs the
+      # sync above — only `docker compose watch` does. Without the mount the
+      # container serves the source baked into the image until it is rebuilt.
+      - ../backend/app:/app/backend/app
     environment:
       SMTP_HOST: "mailcatcher"
       SMTP_PORT: "1025"