feat: inject build version/commit into scraper and UI at docker build time

- Go scraper: Version/Commit vars in main.go, injected via -ldflags; Server struct + New() updated; GET /health and new GET /api/version expose them
- UI Dockerfile: ARG BUILD_VERSION/BUILD_COMMIT → ENV PUBLIC_BUILD_VERSION/PUBLIC_BUILD_COMMIT for SvelteKit
- Footer: shows version+short commit when not 'dev' (text-zinc-800, subtle)
- docker-compose: args blocks for scraper and ui build sections pass $GIT_TAG/$GIT_COMMIT

docker-compose.yml

@@ -82,6 +82,9 @@ services:
     build:
       context: ./scraper
       dockerfile: Dockerfile
+      args:
+        VERSION: "${GIT_TAG:-dev}"
+        COMMIT: "${GIT_COMMIT:-unknown}"
     #container_name: libnovel-scraper
     restart: unless-stopped
     depends_on:
@@ -131,6 +134,9 @@ services:
     build:
       context: ./ui
       dockerfile: Dockerfile
+      args:
+        BUILD_VERSION: "${GIT_TAG:-dev}"
+        BUILD_COMMIT: "${GIT_COMMIT:-unknown}"
     #   container_name: libnovel-ui
     restart: unless-stopped
     depends_on: