Initial commit — DRB server stack

Includes c2-core (FastAPI/MQTT/Firestore), discord-bot (slash commands),
frontend (Next.js admin UI), and mosquitto config.

drb-c2-core/app/config.py

@@ -0,0 +1,24 @@
+from pydantic_settings import BaseSettings
+from typing import Optional
+
+
+class Settings(BaseSettings):
+    # MQTT
+    mqtt_broker: str = "localhost"
+    mqtt_port: int = 1883
+    mqtt_user: Optional[str] = None
+    mqtt_pass: Optional[str] = None
+
+    # GCP
+    gcp_credentials_path: Optional[str] = None  # None → uses ADC
+    gcs_bucket: Optional[str] = None             # None → audio upload disabled
+    firestore_database: str = "(default)"
+
+    # Node health
+    node_offline_threshold: int = 90  # seconds without checkin before marking offline
+
+    class Config:
+        env_file = ".env"
+
+
+settings = Settings()