chore: add .env.example template for bot configuration

.env.example

@@ -0,0 +1,21 @@
+# MoAI Bot Configuration
+# Copy this file to .env and fill in your values
+
+# Telegram Bot Token (required)
+# Get this from @BotFather on Telegram
+BOT_TOKEN=
+
+# Allowed Users (optional)
+# Comma-separated Telegram user IDs that can use the bot
+# Leave empty to allow all users
+# To find your user ID, message @userinfobot on Telegram
+ALLOWED_USERS=
+
+# Database URL (optional)
+# Defaults to SQLite: sqlite+aiosqlite:///./moai.db
+# DATABASE_URL=sqlite+aiosqlite:///./moai.db
+
+# Log Level (optional)
+# Options: DEBUG, INFO, WARNING, ERROR
+# Defaults to INFO
+# LOG_LEVEL=INFO