feat: Initial project scaffold

Flask API backend for ESP32 sensor fleet:
- App factory pattern with blueprints
- SQLAlchemy 2.x models (Sensor, Device, Sighting, Alert, Event, Probe)
- UDP collector for sensor data streams
- REST API endpoints for sensors, devices, alerts, events, probes, stats
- pytest setup with fixtures
- Containerfile for podman deployment
- Makefile for common tasks

Makefile

@@ -0,0 +1,43 @@
+.PHONY: build run dev stop logs test migrate clean install
+
+APP_NAME := esp32-web
+PORT := 5500
+
+install:
+	pip install -e ".[dev]"
+
+dev:
+	flask --app src/esp32_web run --port $(PORT) --debug
+
+test:
+	pytest -v
+
+migrate:
+	flask --app src/esp32_web db upgrade
+
+migrate-init:
+	flask --app src/esp32_web db init
+
+migrate-create:
+	flask --app src/esp32_web db migrate -m "$(msg)"
+
+build:
+	podman build -t $(APP_NAME) .
+
+run:
+	podman run -d --name $(APP_NAME) \
+		-p $(PORT):$(PORT) \
+		-p $(PORT):$(PORT)/udp \
+		-v ./instance:/app/instance:Z \
+		$(APP_NAME)
+
+stop:
+	podman stop $(APP_NAME) && podman rm $(APP_NAME)
+
+logs:
+	podman logs -f $(APP_NAME)
+
+clean:
+	rm -rf __pycache__ .pytest_cache .ruff_cache
+	find . -type d -name __pycache__ -exec rm -rf {} +
+	find . -type f -name "*.pyc" -delete