diff --git a/.devcontainer/setup-ha.sh b/.devcontainer/setup-ha.sh
new file mode 100755
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+++ b/.devcontainer/setup-ha.sh
@@ -0,0 +1,433 @@
+#!/usr/bin/env bash
+# setup-ha.sh - Idempotent Home Assistant setup for TeslaMate development
+#
+# This script:
+# 1. Completes HA onboarding (creates admin user)
+# 2. Adds the alexbelgium addon repository (for PostgreSQL)
+# 3. Installs and starts PostgreSQL 17
+# 4. Installs, configures, and starts the local TeslaMate addon
+#
+# MQTT and Grafana dashboard import are disabled so TeslaMate boots cleanly
+# against PostgreSQL alone. Enable them in the addon configuration once a
+# broker / Grafana instance is available.
+#
+# Usage: bash .devcontainer/setup-ha.sh
+#
+# Safe to run multiple times (idempotent).
+
+set -euo pipefail
+
+HA_URL="http://localhost:8123"
+ALEXBELGIUM_REPO="https://github.com/alexbelgium/hassio-addons"
+ADMIN_USER="admin"
+ADMIN_PASS="pass"
+CLIENT_ID="${HA_URL}/"
+
+POSTGRES_PASSWORD="homeassistant"
+POSTGRES_USER="postgres"
+POSTGRES_DB="teslamate"
+POSTGRES_PORT=5432
+# Addon slug = repo_hash + "_" + addon_slug_from_config
+# Repo hash: first 8 chars of sha1("https://github.com/alexbelgium/hassio-addons")
+POSTGRES_SLUG="db21ed7f_postgres_latest"
+
+TESLAMATE_SLUG="local_teslamate"
+TESLAMATE_PORT=4000
+TIMEZONE="Europe/London"
+
+# Path to the addon's config.json (one level up from this script's directory),
+# resolved independently of the current working directory.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ADDON_DIR="$(dirname "$SCRIPT_DIR")"
+CONFIG_JSON="${ADDON_DIR}/config.json"
+
+# --- Helpers ---
+
+GREEN='\033[0;32m'
+YELLOW='\033[0;33m'
+RED='\033[0;31m'
+CYAN='\033[0;36m'
+BOLD='\033[1m'
+NC='\033[0m' # No Color
+
+log()  { echo -e "${CYAN}==>${NC} ${BOLD}$*${NC}"; }
+warn() { echo -e "${YELLOW}WARNING:${NC} $*" >&2; }
+err()  { echo -e "${RED}ERROR:${NC} $*" >&2; exit 1; }
+ok()   { echo -e "${CYAN}==>${NC} ${GREEN}$*${NC}"; }
+
+# Run Supervisor API call via hassio_cli container
+# IMPORTANT: Use single quotes for outer sh -c argument so $SUPERVISOR_TOKEN
+# is expanded by the inner shell (where the env var exists), not the outer bash.
+supervisor_api() {
+  local method="$1" endpoint="$2"
+  docker exec hassio_cli sh -c \
+    'curl -s -X '"${method}"' -H "Authorization: Bearer $SUPERVISOR_TOKEN" -H "Content-Type: application/json" http://supervisor'"${endpoint}"
+}
+
+supervisor_api_with_body() {
+  local method="$1" endpoint="$2" body="$3"
+  docker exec -e "BODY=${body}" hassio_cli sh -c \
+    'curl -s -X '"${method}"' -H "Authorization: Bearer $SUPERVISOR_TOKEN" -H "Content-Type: application/json" -d "$BODY" http://supervisor'"${endpoint}"
+}
+
+# Query a specific jq field from a Supervisor API response
+# Runs curl and jq inside hassio_cli to avoid docker exec stdout pipe issues
+supervisor_api_jq() {
+  local endpoint="$1" jq_filter="$2"
+  docker exec -e "JQ_FILTER=${jq_filter}" hassio_cli sh -c \
+    'curl -s -H "Authorization: Bearer $SUPERVISOR_TOKEN" http://supervisor'"${endpoint}"' | jq -r "$JQ_FILTER"'
+}
+
+# Check if a jq expression matches (returns 0 if match found, 1 otherwise)
+supervisor_api_jq_test() {
+  local endpoint="$1" jq_filter="$2"
+  docker exec -e "JQ_FILTER=${jq_filter}" hassio_cli sh -c \
+    'curl -s -H "Authorization: Bearer $SUPERVISOR_TOKEN" http://supervisor'"${endpoint}"' | jq -e "$JQ_FILTER" > /dev/null 2>&1'
+}
+
+# --- Step 0: Wait for HA to be ready ---
+
+wait_for_ha() {
+  log "Waiting for Home Assistant to be ready..."
+  local max_attempts=60
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    if curl -sf "${HA_URL}/api/onboarding" > /dev/null 2>&1; then
+      ok "Home Assistant is ready"
+      return 0
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  err "Home Assistant did not become ready in time"
+}
+
+# --- Step 1: Complete onboarding ---
+
+complete_onboarding() {
+  log "Checking onboarding status..."
+  local onboarding
+  onboarding=$(curl -sf "${HA_URL}/api/onboarding")
+
+  local user_done
+  user_done=$(echo "$onboarding" | jq -r '.[] | select(.step == "user") | .done')
+
+  if [ "$user_done" = "true" ]; then
+    ok "Onboarding already completed"
+    return 0
+  fi
+
+  log "Creating admin user '${ADMIN_USER}'..."
+  local auth_response
+  auth_response=$(curl -sf -X POST "${HA_URL}/api/onboarding/users" \
+    -H "Content-Type: application/json" \
+    -d "{\"client_id\":\"${CLIENT_ID}\",\"name\":\"Admin\",\"username\":\"${ADMIN_USER}\",\"password\":\"${ADMIN_PASS}\",\"language\":\"en\"}")
+
+  local auth_code
+  auth_code=$(echo "$auth_response" | jq -r '.auth_code')
+
+  if [ -z "$auth_code" ] || [ "$auth_code" = "null" ]; then
+    err "Failed to create user: ${auth_response}"
+  fi
+
+  # Exchange auth code for access token
+  local token_response
+  token_response=$(curl -sf -X POST "${HA_URL}/auth/token" \
+    --data-urlencode "grant_type=authorization_code" \
+    --data-urlencode "code=${auth_code}" \
+    --data-urlencode "client_id=${CLIENT_ID}")
+
+  local access_token
+  access_token=$(echo "$token_response" | jq -r '.access_token')
+
+  if [ -z "$access_token" ] || [ "$access_token" = "null" ]; then
+    err "Failed to get access token: ${token_response}"
+  fi
+
+  # Complete remaining onboarding steps
+  log "Completing onboarding steps..."
+  curl -sf -X POST "${HA_URL}/api/onboarding/core_config" \
+    -H "Authorization: Bearer ${access_token}" \
+    -H "Content-Type: application/json" \
+    -d "{}" > /dev/null 2>&1 || true
+
+  curl -sf -X POST "${HA_URL}/api/onboarding/analytics" \
+    -H "Authorization: Bearer ${access_token}" \
+    -H "Content-Type: application/json" \
+    -d "{}" > /dev/null 2>&1 || true
+
+  curl -sf -X POST "${HA_URL}/api/onboarding/integration" \
+    -H "Authorization: Bearer ${access_token}" \
+    -H "Content-Type: application/json" \
+    -d "{\"client_id\":\"${CLIENT_ID}\",\"redirect_uri\":\"${HA_URL}/\"}" > /dev/null 2>&1 || true
+
+  ok "Onboarding complete"
+}
+
+# --- Step 2: Add alexbelgium addon repository ---
+
+add_addon_repo() {
+  log "Checking addon repositories..."
+
+  if supervisor_api_jq_test "/store/repositories" ".data[] | select(.source == \"${ALEXBELGIUM_REPO}\")"; then
+    ok "Repository already added: ${ALEXBELGIUM_REPO}"
+    return 0
+  fi
+
+  log "Adding addon repository: ${ALEXBELGIUM_REPO}"
+  supervisor_api_with_body POST "/store/repositories" \
+    "{\"repository\":\"${ALEXBELGIUM_REPO}\"}" > /dev/null
+
+  # Wait for the store to refresh by checking if the postgres addon is available
+  log "Waiting for store to refresh..."
+  local max_attempts=60
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    if supervisor_api_jq_test "/addons/${POSTGRES_SLUG}/info" '.data.name'; then
+      ok "Store refreshed successfully"
+      return 0
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  err "Store did not refresh in time - postgres addon not found"
+}
+
+# --- Step 3: Install PostgreSQL ---
+
+install_postgres() {
+  local postgres_slug="$1"
+
+  log "Checking PostgreSQL addon status (${postgres_slug})..."
+  local version
+  version=$(supervisor_api_jq "/addons/${postgres_slug}/info" '.data.version // empty')
+
+  if [ -n "$version" ]; then
+    local state
+    state=$(supervisor_api_jq "/addons/${postgres_slug}/info" '.data.state')
+    ok "PostgreSQL addon already installed (version: ${version}, state: ${state})"
+    return 0
+  fi
+
+  log "Installing PostgreSQL addon..."
+  supervisor_api POST "/addons/${postgres_slug}/install" > /dev/null
+
+  # Wait for installation to complete
+  log "Waiting for PostgreSQL installation..."
+  local max_attempts=120
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    version=$(supervisor_api_jq "/addons/${postgres_slug}/info" '.data.version // empty')
+    if [ -n "$version" ]; then
+      ok "PostgreSQL addon installed (version: ${version})"
+      return 0
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  err "PostgreSQL addon installation timed out"
+}
+
+# --- Step 4: Configure and start PostgreSQL ---
+
+configure_and_start_postgres() {
+  local postgres_slug="$1"
+
+  log "Configuring PostgreSQL addon..."
+  local options_json
+  options_json=$(jq -n \
+    --arg pw "$POSTGRES_PASSWORD" \
+    --arg db "$POSTGRES_DB" \
+    '{options: {POSTGRES_PASSWORD: $pw, POSTGRES_DB: $db, env_vars: []}}')
+
+  supervisor_api_with_body POST "/addons/${postgres_slug}/options" \
+    "${options_json}" > /dev/null
+
+  # Check if already running
+  local state
+  state=$(supervisor_api_jq "/addons/${postgres_slug}/info" '.data.state')
+
+  if [ "$state" = "started" ]; then
+    ok "PostgreSQL addon already running"
+    return 0
+  fi
+
+  log "Starting PostgreSQL addon..."
+  supervisor_api POST "/addons/${postgres_slug}/start" > /dev/null
+
+  # Wait for postgres to be ready
+  log "Waiting for PostgreSQL to be ready..."
+  local max_attempts=60
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    state=$(supervisor_api_jq "/addons/${postgres_slug}/info" '.data.state')
+    if [ "$state" = "started" ]; then
+      ok "PostgreSQL addon is running"
+      # Give postgres time to initialize the database
+      sleep 10
+      return 0
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  err "PostgreSQL addon did not start in time"
+}
+
+# --- Step 5: Install and configure TeslaMate ---
+
+# Remove the "image" key from config.json so the Supervisor builds the addon
+# image locally from the Dockerfile instead of pulling a pre-built image.
+remove_addon_image() {
+  log "Ensuring TeslaMate addon builds locally..."
+
+  if [ ! -f "$CONFIG_JSON" ]; then
+    err "config.json not found at ${CONFIG_JSON}"
+  fi
+
+  if ! jq -e 'has("image")' "$CONFIG_JSON" > /dev/null 2>&1; then
+    ok "config.json already has no 'image' key - addon will build locally"
+    return 0
+  fi
+
+  jq 'del(.image)' "$CONFIG_JSON" > "${CONFIG_JSON}.tmp" && mv "${CONFIG_JSON}.tmp" "$CONFIG_JSON"
+  ok "Removed 'image' key from config.json"
+
+  # Reload the store so the Supervisor re-reads the local addon config
+  log "Reloading addon store..."
+  supervisor_api POST "/store/reload" > /dev/null
+}
+
+install_teslamate() {
+  log "Checking TeslaMate addon status..."
+  local version
+  version=$(supervisor_api_jq "/addons/${TESLAMATE_SLUG}/info" '.data.version // empty')
+
+  if [ -n "$version" ]; then
+    local state
+    state=$(supervisor_api_jq "/addons/${TESLAMATE_SLUG}/info" '.data.state')
+    ok "TeslaMate addon already installed (version: ${version}, state: ${state})"
+    return 0
+  fi
+
+  log "Installing TeslaMate addon..."
+  supervisor_api POST "/addons/${TESLAMATE_SLUG}/install" > /dev/null
+
+  # Wait for installation to complete (the TeslaMate image is large)
+  log "Waiting for TeslaMate installation..."
+  local max_attempts=120
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    version=$(supervisor_api_jq "/addons/${TESLAMATE_SLUG}/info" '.data.version // empty')
+    if [ -n "$version" ]; then
+      ok "TeslaMate addon installed (version: ${version})"
+      return 0
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  err "TeslaMate addon installation timed out"
+}
+
+configure_and_start_teslamate() {
+  local postgres_slug="$1"
+
+  # Derive the postgres hostname from its slug (underscores -> hyphens)
+  local postgres_host
+  postgres_host=$(echo "$postgres_slug" | tr '_' '-')
+
+  log "Configuring TeslaMate addon (db host: ${postgres_host})..."
+
+  # Fetch the addon's current options - already populated with defaults - and overlay only
+  # the values we need to change.
+  local current_options overrides options_json
+  current_options=$(supervisor_api_jq "/addons/${TESLAMATE_SLUG}/info" '.data.options')
+  overrides=$(jq -n \
+    --arg user "$POSTGRES_USER" \
+    --arg pass "$POSTGRES_PASSWORD" \
+    --argjson port "$POSTGRES_PORT" \
+    --arg host "$postgres_host" \
+    --arg db "$POSTGRES_DB" \
+    --arg tz "$TIMEZONE" \
+    '{database_user: $user, database_pass: $pass, database_port: $port, database_host: $host, database_name: $db, database_ssl: false, disable_mqtt: true, grafana_import_dashboards: false, timezone: $tz}')
+  options_json=$(jq -n --argjson cur "$current_options" --argjson ovr "$overrides" '{options: ($cur + $ovr)}')
+
+  local response
+  response=$(supervisor_api_with_body POST "/addons/${TESLAMATE_SLUG}/options" "${options_json}")
+  if [ "$(echo "$response" | jq -r '.result')" != "ok" ]; then
+    err "Failed to set TeslaMate options: $(echo "$response" | jq -r '.message // .')"
+  fi
+
+  # Check if already running
+  local state
+  state=$(supervisor_api_jq "/addons/${TESLAMATE_SLUG}/info" '.data.state')
+
+  if [ "$state" = "started" ]; then
+    ok "TeslaMate addon already running"
+    wait_for_teslamate_ready
+    return 0
+  fi
+
+  log "Starting TeslaMate addon..."
+  supervisor_api POST "/addons/${TESLAMATE_SLUG}/start" > /dev/null
+
+  # Wait for addon state to become "started"
+  log "Waiting for TeslaMate addon to start..."
+  local max_attempts=60
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    state=$(supervisor_api_jq "/addons/${TESLAMATE_SLUG}/info" '.data.state')
+    if [ "$state" = "started" ]; then
+      break
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  if [ "$state" != "started" ]; then
+    err "TeslaMate addon did not start in time (state: ${state})"
+  fi
+
+  wait_for_teslamate_ready
+  ok "TeslaMate addon started and ready"
+}
+
+wait_for_teslamate_ready() {
+  log "Waiting for TeslaMate to be ready (listening on port ${TESLAMATE_PORT})..."
+  local max_attempts=60
+  local attempt=0
+  while [ "$attempt" -lt "$max_attempts" ]; do
+    local logs
+    logs=$(supervisor_api GET "/addons/${TESLAMATE_SLUG}/logs" 2>/dev/null || true)
+    if echo "$logs" | grep -q "TeslaMateWeb.Endpoint"; then
+      ok "TeslaMate is ready"
+      return 0
+    fi
+    sleep 5
+    attempt=$((attempt + 1))
+  done
+  err "TeslaMate did not become ready in time (never saw 'TeslaMateWeb.Endpoint' in logs)"
+}
+
+# --- Main ---
+
+main() {
+  log "Setting up Home Assistant for TeslaMate development"
+  echo ""
+
+  wait_for_ha
+  complete_onboarding
+  add_addon_repo
+
+  install_postgres "$POSTGRES_SLUG"
+  configure_and_start_postgres "$POSTGRES_SLUG"
+  remove_addon_image
+  install_teslamate
+  configure_and_start_teslamate "$POSTGRES_SLUG"
+
+  echo ""
+  ok "Setup complete!"
+  log "  Home Assistant: ${HA_URL} (user: ${ADMIN_USER}, pass: ${ADMIN_PASS})"
+  log "  PostgreSQL: ${POSTGRES_SLUG} (user: ${POSTGRES_USER}, db: ${POSTGRES_DB})"
+  log "  TeslaMate: open the TeslaMate panel via HA ingress (${HA_URL})"
+}
+
+main "$@"