Initial standalone dectalk TTS server extracted from the ttstoy bot cog

Self-contained HTTP service with engine, data, start script, systemd unit,
and documentation. Runs independently of the Discord bot on its fixed port.

INSTALL.md

@@ -0,0 +1,43 @@
+# Installing the DECTalk TTS Server as a system service
+
+These steps install the server as a systemd service that starts on boot and
+restarts automatically if it crashes. Commands that need root are shown with
+`sudo`; run them in your own terminal.
+
+## 1. Install prerequisites
+
+```bash
+sudo apt install ffmpeg nodejs npm
+```
+
+## 2. Install node dependencies
+
+```bash
+cd /home/owen/dectalk-tts-server
+npm install
+```
+
+## 3. Install the systemd unit
+
+```bash
+sudo cp /home/owen/dectalk-tts-server/dectalk-tts-server.service /etc/systemd/system/
+sudo systemctl daemon-reload
+sudo systemctl enable --now dectalk-tts-server
+```
+
+## 4. Verify
+
+```bash
+systemctl status dectalk-tts-server
+curl -s http://127.0.0.1:33001/health
+```
+
+The health endpoint should return `{"status":"ok"}`.
+
+## Managing the service
+
+```bash
+sudo systemctl restart dectalk-tts-server
+sudo systemctl stop dectalk-tts-server
+journalctl -u dectalk-tts-server -f
+```