Load .env before app imports to ensure environment variables are available

Move load_dotenv() call before all app.* imports in main.py to fix the
import-time environment variable loading issue.

Problem:
- Previously, load_dotenv() was called AFTER importing app.* modules
- When app.api.client was imported, it read BACKEND_URL at import time
- At that moment, .env was not yet loaded, so it used the hardcoded default
- This caused the bot to connect to wrong backend port even when .env was
  correctly configured

Solution:
- Move load_dotenv() to line 20-21, immediately after standard library imports
- This ensures .env is loaded BEFORE any app.* modules are imported
- Now all modules see the correct environment variables from .env file
- Also updated BACKEND_URL default from 8001 to 8000 for consistency

Flow now:
1. Import standard libraries (os, Path, dotenv, etc.)
2. Load .env file (line 20-21) ✅
3. Import app.* modules (which can now read env vars correctly) ✅
4. Import telegram-python-bot and other dependencies
5. Start application

This follows Python best practices for environment variable loading and
ensures reliable configuration loading in Windows Service deployments.

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

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

reports-app/telegram-bot/app/main.py

@@ -13,6 +13,13 @@ from dotenv import load_dotenv
 import uvicorn
 from threading import Thread
 
+# ============================================================================
+# LOAD ENVIRONMENT VARIABLES FIRST - BEFORE ANY APP IMPORTS
+# ============================================================================
+# This ensures all modules can access environment variables at import time
+env_path = Path(__file__).parent.parent / '.env'
+load_dotenv(env_path)
+
 # Telegram imports
 from telegram.ext import (
     Application,
@@ -61,13 +68,9 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
-# Load environment variables
-env_path = Path(__file__).parent.parent / '.env'
-load_dotenv(env_path)
-
-# Environment variables
+# Environment variables (already loaded above)
 TELEGRAM_BOT_TOKEN = os.getenv('TELEGRAM_BOT_TOKEN')
-BACKEND_URL = os.getenv('BACKEND_URL', 'http://localhost:8001')
+BACKEND_URL = os.getenv('BACKEND_URL', 'http://localhost:8000')
 INTERNAL_API_PORT = int(os.getenv('INTERNAL_API_PORT', '8002'))