feat: make libraries volume path configurable via env variable

- Add LIBRARIES_HOST_PATH env variable for Docker volume mount path
- Update docker-compose.yml to use ${LIBRARIES_HOST_PATH:-../libraries}
- Update .env.example with new variable and documentation
- Allows users to customize the host path for their libraries folder

.env.example

@@ -44,7 +44,12 @@ MEILI_URL=http://meilisearch:7700
 # Storage Configuration
 # =============================================================================
 
-# Path to libraries directory
+# Path to libraries directory inside container
 # In Docker: leave as default /libraries
 # For local dev: set to your local libraries folder path
 LIBRARIES_ROOT_PATH=/libraries
+
+# Path to libraries directory on host machine (for Docker volume mount)
+# Default: ../libraries (relative to infra/docker-compose.yml)
+# You can change this to an absolute path on your machine
+LIBRARIES_HOST_PATH=../libraries