refactor: revert to pre-built image and simplify docs

- Revert docker-compose.yml to use ghcr.io image instead of local build
- Comment out SEARCH_HIGHLIGHT_LIMIT environment variable (users can uncomment if needed)
- Simplify README by removing redundant Docker Compose usage examples
- Change 'several environment variables' to 'environment variables' in docs

Author: Raffael Herrmann

README.md

@@ -98,7 +98,7 @@ volumes:
 
 ### Configuration Options
 
-massCode Web supports several environment variables for customization:
+massCode Web supports environment variables for customization:
 
 #### SEARCH_HIGHLIGHT_LIMIT
 
@@ -123,17 +123,6 @@ environment:
 # No environment variable needed
 ```
 
-**Usage with Docker Compose:**
-
-```bash
-# Set via environment variable
-SEARCH_HIGHLIGHT_LIMIT=10 docker-compose up -d
-
-# Or add to docker-compose.yml
-environment:
-  - SEARCH_HIGHLIGHT_LIMIT=10
-```
-
 ### Manual Docker Run
 
 ```bash

docker-compose.yml

@@ -1,11 +1,10 @@
 services:
   masscode-web:
-    build:
-      context: .
+    image: ghcr.io/codebude/masscode-web:latest
     ports:
       - "8080:80"
     volumes:
       - ./db.json:/data/db.json:ro
-    environment:
-      - SEARCH_HIGHLIGHT_LIMIT=${SEARCH_HIGHLIGHT_LIMIT:-3}
+    #environment:
+    #  - SEARCH_HIGHLIGHT_LIMIT=3
     restart: unless-stopped