Change API token environment variable from API_TOKEN to BRIGHTDATA_API_TOKEN

- Update code to use BRIGHTDATA_API_TOKEN instead of API_TOKEN
- Update error message and documentation
- Update README.md with new environment variable name

Author: עידן וילנסקי

README.md

@@ -35,7 +35,7 @@ from brightdata import bdclient
 client = bdclient(api_token="your_api_token_here")
 
 # Or using environment variables
-# Set API_TOKEN in your environment or .env file
+# Set BRIGHTDATA_API_TOKEN in your environment or .env file
 client = bdclient()
 ```
 
@@ -107,7 +107,7 @@ print(f"Found {len(zones)} zones")
 Create a `.env` file in your project root:
 
 ```env
-API_TOKEN=your_bright_data_api_token
+BRIGHTDATA_API_TOKEN=your_bright_data_api_token
 WEB_UNLOCKER_ZONE=your_web_unlocker_zone  # Optional
 BROWSER_ZONE=your_browser_zone            # Optional  
 SERP_ZONE=your_serp_zone                 # Optional

brightdata.py

@@ -42,7 +42,7 @@ def __init__(
         #### Create an account at https://brightdata.com/ to get your API token.
 
         Args:
-            api_token: Your Bright Data API token (can also be set via API_TOKEN env var)
+            api_token: Your Bright Data API token (can also be set via BRIGHTDATA_API_TOKEN env var)
             auto_create_zones: Automatically create required zones if they don't exist (default: True)
             web_unlocker_zone: Custom zone name for web unlocker (default: from env or 'sdk_unlocker')
             browser_zone: Custom zone name for browser API (default: from env or 'sdk_browser')
@@ -52,9 +52,9 @@ def __init__(
             load_dotenv()
         except ImportError:
             pass
-        self.api_token = api_token or os.getenv('API_TOKEN')
+        self.api_token = api_token or os.getenv('BRIGHTDATA_API_TOKEN')
         if not self.api_token:
-            raise ValueError("API token is required. Provide it as parameter or set API_TOKEN environment variable")
+            raise ValueError("API token is required. Provide it as parameter or set BRIGHTDATA_API_TOKEN environment variable")
         self.web_unlocker_zone = web_unlocker_zone or os.getenv('WEB_UNLOCKER_ZONE', 'sdk_unlocker')
         self.browser_zone = browser_zone or os.getenv('BROWSER_ZONE', 'sdk_browser')
         self.serp_zone = os.getenv('SERP_ZONE', 'sdk_serp')