Add Telegram watcher, dashboard docs, and deployment config

- scripts/telegram-watcher.js: push ENTER signals from signals.csv to Telegram
- DASHBOARD_GUIDE.md: complete dashboard field-by-field documentation
- package.json: add watch:telegram npm script
- .env.example: deployment env template
- .gitignore: exclude ecosystem.config.cjs/start.sh (server-only with paths)

Watcher reads recommendation column and triggers on:
  - transition NO_TRADE -> ENTER:side
  - flip ENTER:UP <-> ENTER:DOWN
  - 30s cooldown prevents spam

package.json

@@ -4,7 +4,8 @@
   "type": "module",
   "private": true,
   "scripts": {
-    "start": "node src/index.js"
+    "start": "node src/index.js",
+    "watch:telegram": "node scripts/telegram-watcher.js"
   },
   "dependencies": {
     "ethers": "^6.11.1",