Fix business filtering logic and add docker sync guide

DOCKER_SYNC_GUIDE.md

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+# Docker Code Sync Guide
+
+If you have made changes to the backend code and they don't seem to take effect (even though the files on disk are updated), it's because the Docker container is running from a pre-compiled `dist/` directory.
+
+### The Problem
+The `bizmatch-app` container compiles the TypeScript code *only once* when the container starts. It does not automatically watch for changes and recompile while running.
+
+### The Solution
+You must restart or recreate the container to trigger a new build.
+
+**Option 1: Quick Restart (Recommended)**
+Run this in the `bizmatch-server` directory:
+```bash
+docker-compose restart app
+```
+
+**Option 2: Force Rebuild (If changes aren't picked up)**
+If a simple restart doesn't work, use this to force a fresh build:
+```bash
+docker-compose up -d --build app
+```
+
+### Summary for Other Laptops
+1. **Pull** the latest changes from Git.
+2. **Execute** `docker-compose restart app`.
+3. **Verify** the logs for the new `WARN` debug messages.
+.