Enhance configuration to support loading IMAP password and OpenRouter API key from files, and update README with new settings

README.md

@@ -46,12 +46,18 @@ The application uses a YAML configuration file (`config.yaml`) with the followin
 - `server`: IMAP server hostname (e.g., "imap.gmail.com")
 - `port`: IMAP port (typically 993 for TLS)
 - `username`: Your email address
-- `password`: Email password (use ${IMAP_PASSWORD} to load from environment)
+- `password`: Email password (use ${IMAP_PASSWORD} to load from environment or file:///path/to/password.txt to read from file)
 - `mailbox_in`: Mailbox to check for new emails (e.g., "INBOX")
 - `draft_box`: Folder to save AI-generated drafts (e.g., "Drafts")
 - `processed_box`: Folder to move processed emails to (they will also be marked as read)
 - `use_tls`: Whether to use TLS for connection (recommended: true)
 
+### AI Settings
+- `openrouter_api_key`: Your OpenRouter API key (use ${OPENROUTER_API_KEY} to load from environment or file:///path/to/key.txt to read from file)
+- `model`: The AI model to use (e.g., "anthropic/claude-2")
+- `temperature`: Response randomness (0.0-1.0)
+- `max_tokens`: Maximum response length
+
 ```yaml
 imap:
   server: "imap.example.com"