fix(docker): mount Flashpoint read-write by default

The shipped compose mounted the Flashpoint directory read-only, so every write
the app makes to it failed: recording downloaded state in flashpoint.sqlite,
saving downloaded game data under Data/Games, and metadata sync. The Downloaded
page marked nothing and the reconciler warned on every boot.

Drop :ro from both compose files and the README's snippet, and correct the docs
that described the mount as read-only.

docker-compose.yml

@@ -25,7 +25,9 @@ services:
       # Serves both the UI and the API (/api, /game-proxy, /game-zip) on one port
       - "${WEB_PORT:-80}:3100"
     volumes:
-      - ${FLASHPOINT_HOST_PATH:?FLASHPOINT_HOST_PATH is required}:/data/flashpoint:ro
+      # Read-write: the app records downloaded state in flashpoint.sqlite and
+      # writes downloaded game data under Data/Games.
+      - ${FLASHPOINT_HOST_PATH:?FLASHPOINT_HOST_PATH is required}:/data/flashpoint
       - ${DATA_PATH:-./data}:/app/data
       - ${LOGS_PATH:-./logs}:/app/logs
     environment: