Replace native interface with external packet capture and rename receiver to observer

Remove the meshcore_interface component in favor of external
meshcore-packet-capture for data ingestion. Rename receiver_node_id
to observer_node_id across all models, schemas, handlers, and API
routes. Add Alembic migration for the column/table renames. Fix
frontend JS property name mismatch that prevented the Receiver column
from displaying observer data.

.env.example

@@ -4,15 +4,15 @@
 # Configuration is grouped by service. Most deployments only need:
 # - Common Settings (always required)
 # - MQTT Settings (always required)
-# - Interface Settings (for receiver/sender services)
+# - Packet Capture Settings (for observer nodes)
 #
 # The Collector, API, and Web services typically run as a combined "core"
 # profile and share the same data directory.
 #
 # -----------------------------------------------------------------------------
-# QUICK START: Receiver/Sender Only
+# QUICK START: Observer Node
 # -----------------------------------------------------------------------------
-# For a minimal receiver or sender setup, you only need these settings:
+# For an observer node capturing mesh traffic, you need:
 #
 #   MQTT_HOST=your-mqtt-broker.example.com
 #   MQTT_PORT=1883
@@ -59,7 +59,7 @@ SEED_HOME=./seed
 # =============================================================================
 # MQTT SETTINGS
 # =============================================================================
-# MQTT broker connection settings for interface, collector, and API services
+# MQTT broker connection settings for collector and API services
 
 # MQTT Broker host
 # When using the local MQTT broker (--profile mqtt), use "mqtt"
@@ -92,54 +92,21 @@ MQTT_WS_PATH=/mqtt
 MQTT_EXTERNAL_PORT=1883
 MQTT_WS_PORT=9001
 
-# =============================================================================
-# INTERFACE SETTINGS (Receiver/Sender)
-# =============================================================================
-# Settings for the MeshCore device interface services
-
-# Serial port for receiver device
-SERIAL_PORT=/dev/ttyUSB0
-
-# Serial port for sender device (if using separate device)
-SERIAL_PORT_SENDER=/dev/ttyUSB1
-
-# Baud rate for serial communication
-SERIAL_BAUD=115200
-
-# Optional device/node name to set on startup
-# This name is broadcast to the mesh network in advertisements
-MESHCORE_DEVICE_NAME=
-
-# Optional node address override (64-char hex string)
-# Only set if you need to override the device's public key
-NODE_ADDRESS=
-NODE_ADDRESS_SENDER=
-
-# -------------------
-# Contact Cleanup Settings (RECEIVER mode only)
-# -------------------
-# Automatic removal of stale contacts from the MeshCore companion node
-
-# Enable automatic removal of stale contacts from companion node
-CONTACT_CLEANUP_ENABLED=true
-
-# Remove contacts not advertised for this many days
-CONTACT_CLEANUP_DAYS=7
-
 # =============================================================================
 # PACKET CAPTURE SETTINGS
 # =============================================================================
 # External packet capture service (ghcr.io/agessaman/meshcore-packet-capture)
-# Replaces the native interface-receiver. Uses the "receiver" compose profile.
+# See https://github.com/agessaman/meshcore-packet-capture for documentation.
+# Uses the "receiver" compose profile.
 # Publishes captured packets to MQTT in LetsMesh upload format, ingested by
-# the collector with COLLECTOR_INGEST_MODE=letsmesh_upload.
+# the collector.
+
+# Serial port for the packet capture device
+SERIAL_PORT=/dev/ttyUSB0
 
 # Docker image version tag for the packet capture image
 PACKETCAPTURE_IMAGE_VERSION=latest
 
-# Serial port for the packet capture device (reuses SERIAL_PORT by default)
-# PACKETCAPTURE_SERIAL_PORT=/dev/ttyUSB0
-
 # Connection timeout and retry settings
 PACKETCAPTURE_TIMEOUT=30
 PACKETCAPTURE_MAX_CONNECTION_RETRIES=5
@@ -195,13 +162,7 @@ PACKETCAPTURE_EXIT_ON_RECONNECT_FAIL=true
 # =============================================================================
 # The collector subscribes to MQTT events and stores them in the database
 
-# Collector MQTT ingest mode
-# - native: expects <prefix>/<pubkey>/event/<event_name> topics (native interface-receiver)
-# - letsmesh_upload: expects LetsMesh observer uploads on
-#   <prefix>/<pubkey>/(packets|status|internal)
-COLLECTOR_INGEST_MODE=letsmesh_upload
-
-# LetsMesh decoder support (used only when COLLECTOR_INGEST_MODE=letsmesh_upload)
+# LetsMesh decoder support
 # Set to false to disable external packet decoding
 COLLECTOR_LETSMESH_DECODER_ENABLED=true
 
@@ -275,7 +236,7 @@ NODE_CLEANUP_DAYS=7
 # =============================================================================
 # API SETTINGS
 # =============================================================================
-# REST API for querying data and sending commands
+# REST API for querying data
 
 # External API port
 API_PORT=8000