Add shared Docker network and Miniflux plugin for Hermes

- Create external 'monotrope' Docker network so services can
  communicate by container name
- Add Miniflux to the shared network (db stays on internal network)
- Add Hermes Miniflux plugin with list_feeds and get_unread_entries tools
- Mount plugin directory and pass Miniflux API key to Hermes container

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

infra/hermes/plugins/miniflux/plugin.yaml

@@ -0,0 +1,10 @@
+name: miniflux
+version: 1.0.0
+description: Read feeds and entries from the local Miniflux RSS reader
+requires_env:
+  MINIFLUX_API_KEY:
+    description: Miniflux API key (generate in Miniflux → Settings → API Keys)
+    secret: true
+provides_tools:
+  - list_feeds
+  - get_unread_entries