Fix scheduled events not executing due to property name mismatch

The scheduler was correctly scheduling events but they weren't executing because the code was checking for camelCase property names (channelId, pingRoleId) while the database returns snake_case names (channel_id, ping_role_id). This caused channel and role validation to be skipped, resulting in silent failures.

Also added sqlite3 CLI to Docker container for debugging database issues.

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

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

Dockerfile

@@ -1,6 +1,8 @@
 # Use Node 20 LTS with full Debian for better compatibility
 FROM node:20
 
+RUN apt update && apt install -y sqlite3
+
 WORKDIR /app
 
 # Copy package files (npm will work better for native modules in Docker)