feat: initial KosmoConnect platform v0.1

Includes:
- Backend services: ingestion (:8001), weather API (:8002),
  gateway (:8003), billing (:8004) with BTCPay integration
- Shared asyncpg pool, TimescaleDB hypertable, Redis, Mosquitto MQTT
- React frontend: Dashboard (MapLibre) and Messaging (chat UI)
- Bridge daemon for Pi + Meshtastic (Serial/TCP T-Deck support)
- Production Docker Compose, Nginx reverse proxy, ops scripts
- DEPLOY.md with step-by-step deployment guide

tests/README.md

@@ -0,0 +1,49 @@
+# Tests
+
+This directory contains integration, end-to-end, and hardware-in-the-loop tests for the KosmoConnect platform.
+
+## Structure
+
+```
+tests/
+├── integration/          # Service-level integration tests
+│   ├── api/              # API contract tests
+│   ├── gateway/          # Message gateway flow tests
+│   ├── ingestion/        # Data pipeline tests
+│   └── e2e/              # Full end-to-end scenarios
+└── hardware-in-loop/     # Physical hardware validation
+    ├── enviro-node/      # Enviro-node firmware tests
+    ├── bridge/           # Bridge daemon tests
+    └── fixtures/         # Shared test data and mock devices
+```
+
+## Integration Tests
+
+Run against a local Docker Compose stack of all backend services.
+
+**Scenarios**:
+1. **Data Ingestion E2E**: Simulate a bridge publishing MQTT messages → verify data appears in API response
+2. **Message Gateway E2E**: Simulate web user sending message → verify MQTT topic receives payload → simulate ACK → verify delivery status updated
+3. **Subscription Enforcement**: Attempt to send message with expired subscription → verify 403 response
+4. **Rate Limiting**: Send burst of messages → verify 429 response
+
+## Hardware-in-the-Loop Tests
+
+Requires physical test hardware on a lab bench.
+
+**Setup**:
+- 1x Enviro-Node prototype on test fixture
+- 1x Infrastructure Node (T-Beam) connected to test Raspberry Pi
+- Local test MQTT broker
+- RF isolation box (optional, for CI)
+
+**Scenarios**:
+1. **Sensor Accuracy**: Compare enviro-node readings against calibrated reference instruments
+2. **Store-and-Forward**: Disconnect bridge node, let enviro-node collect data, reconnect bridge, verify all data is transmitted
+3. **Power Budget**: Run enviro-node on small battery for 72 hours, verify expected sleep currents
+4. **Mesh Relay**: Send message between two handheld Meshtastic devices via the enviro-node relay
+
+## CI Integration
+
+- Integration tests run on every PR via GitHub Actions
+- Hardware-in-the-loop tests run nightly on a self-hosted runner connected to the lab bench