migrate from gotify to ntfy with image attachment support

- Replace GotifyNotifier with NtfyNotifier for push notifications
- Add support for sending email image attachments to ntfy
- Add NTFY_URL, NTFY_TOKEN, NTFY_TOPIC environment variables
- Add get_mailpit_image() and get_mailpit_image_thumb() helpers
- Sanitize message content for HTTP headers (remove newlines)
- Remove all gotify references

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

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

CLAUDE.md

@@ -0,0 +1,68 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Sneaky Mon is an email-to-notification bridge that receives webhooks from Mailpit (local email service) and forwards emails as push notifications to Gotify or Ntfy. Designed for monitoring system-generated emails (e.g., IoT camera motion alerts) on secure internal networks.
+
+## Commands
+
+### Development
+```bash
+# Setup virtual environment
+python3 -m venv venv
+source venv/bin/activate
+pip install -r requirements.txt
+
+# Run Flask server (listens on 0.0.0.0:8088)
+python app/main.py
+
+# Test with hardcoded message ID
+python app/dev_main.py
+```
+
+### Docker
+```bash
+# Start services (Mailpit + webhook handler)
+docker-compose up -d
+
+# View logs
+docker-compose logs -f sneaky_mon_webhook
+
+# Build and push image
+./build_push_image.sh
+```
+
+## Architecture
+
+```
+Email Sources → Mailpit (SMTP:1025, API:8025) → Sneaky Mon (POST /hook) → Ntfy/Gotify
+```
+
+**Data Flow:**
+1. Email arrives at Mailpit SMTP
+2. Mailpit triggers webhook to `/hook` endpoint
+3. Flask app fetches full message from Mailpit API
+4. Extracts subject/content, creates notification
+5. Sends to Ntfy or Gotify
+
+## Key Files
+
+- `app/main.py` - Flask app with `/hook` webhook endpoint and core logic
+- `app/utils/gotify_api.py` - GotifyNotifier class for Gotify integration
+- `app/utils/ntfy_api.py` - NtfyNotifier class for Ntfy integration
+- `docker-compose.yaml` - Orchestrates Mailpit and webhook services
+
+## Configuration
+
+All configuration via environment variables (see `.env.example`):
+- `MAILPIT_API` / `MAILPIT_TOKEN` - Mailpit REST API access
+- `NTFY_URL` / `NTFY_TOKEN` / `NTFY_TOPIC` - Ntfy notification service (primary)
+- `GOTIFY_URL` / `GOTIFY_TOKEN` - Gotify notification service (legacy, optional)
+- `LOG_LEVEL` - Logging verbosity
+
+## Current State Notes
+
+- Project uses Ntfy for push notifications with image attachment support
+- Application intentionally lacks TLS/auth - designed for isolated internal VLANs