Compact home page entries; set up Compose for Arcane git sync

Podium, Spotlight and Grid render smaller on the home page on desktop so
one entry no longer fills the screen; list pages keep full size.

Compose now builds on every deploy (pull_policy: build), stores data in
the canon-data named volume outside the synced folder (CANON_DATA_PATH
overrides), and takes optional bind/port/version settings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -1,21 +1,37 @@
 name: canon
 
+# Works with a plain `docker compose up -d --build` and with Arcane's Git sync
+# (Pull). Arcane pulls this file's whole directory, so the build context is
+# the repository itself.
+
 services:
   canon:
-    build: .
+    build:
+      context: .
+      args:
+        VERSION: ${CANON_VERSION:-dev}
     image: canon:latest
+    # Never look for canon:latest on a registry: every deploy (including
+    # Arcane's "Pull image" / "Redeploy after sync") builds from the source
+    # that was just synced.
+    pull_policy: build
     container_name: canon
     restart: unless-stopped
     ports:
-      - "0.0.0.0:4242:4242"
+      - "${CANON_BIND:-0.0.0.0}:${CANON_PUBLISH_PORT:-4242}:4242"
     volumes:
-      - ./data:/data
+      # A named volume by default, so a Git sync never touches the database.
+      # Set CANON_DATA_PATH to a host folder (e.g. ./data) to keep it there.
+      - ${CANON_DATA_PATH:-canon-data}:/data
     env_file:
       - path: .env
         required: false
     networks:
       - chromanet
 
+volumes:
+  canon-data:
+
 networks:
   chromanet:
     external: true