Configure Docker for Linux host networking and add startup reindex

- Switch to host network mode for direct access to Ollama on host
- Update OLLAMA_URL to use localhost:11434
- Add startup.sh script to trigger reindex before app starts
- Update Dockerfile to execute startup script

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

startup.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+echo "Starting reindex process..."
+python main.py "" --reindex
+
+echo "Starting Flask application..."
+python app.py