Deploy sgardd to rift and add persistent remote config.

Deployment: Dockerfile + docker-compose for sgardd on rift behind mc-proxy
(L4 SNI passthrough on :9443, multiplexed with metacrypt gRPC). TLS via
Metacrypt-issued cert, SSH-key auth.

CLI: `sgard remote set/show` saves addr, TLS, and CA path to
<repo>/remote.yaml so push/pull work without flags.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

deploy/docker/docker-compose-rift.yml

@@ -0,0 +1,16 @@
+services:
+  sgardd:
+    image: localhost/sgardd:latest
+    container_name: sgardd
+    restart: unless-stopped
+    user: "0:0"
+    ports:
+      - "127.0.0.1:19473:9473"
+    volumes:
+      - /srv/sgard:/srv/sgard
+    healthcheck:
+      test: ["CMD", "true"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 10s