fix: port main branch changes to channel subpackages after rebase

Port changes that were applied to the old pkg/channels/*.go files on main
to their new locations in channel subpackages:
- telegram: precompile regex, var transcribedText, GetModelName()
- discord: var transcribedText declaration
- onebot: resp.Body.Close(), "canceled" spelling, remove empty line
- slack: named return values in parseSlackChatID
- wecom: remove sendMarkdownMessage dead code
- whatsapp: resp.Body.Close() after Dial
- gateway/helpers: remove unused errors import

pkg/channels/onebot/onebot.go

@@ -172,7 +172,10 @@ func (c *OneBotChannel) connect() error {
 		header["Authorization"] = []string{"Bearer " + c.config.AccessToken}
 	}
 
-	conn, _, err := dialer.Dial(c.config.WSUrl, header)
+	conn, resp, err := dialer.Dial(c.config.WSUrl, header)
+	if resp != nil {
+		resp.Body.Close()
+	}
 	if err != nil {
 		return err
 	}
@@ -313,7 +316,7 @@ func (c *OneBotChannel) sendAPIRequest(action string, params any, timeout time.D
 	case <-time.After(timeout):
 		return nil, fmt.Errorf("API request %s timed out after %v", action, timeout)
 	case <-c.ctx.Done():
-		return nil, fmt.Errorf("context cancelled")
+		return nil, fmt.Errorf("context canceled")
 	}
 }
 
@@ -815,7 +818,6 @@ func (c *OneBotChannel) parseMessageSegments(
 			textParts = append(textParts, "[forward message]")
 
 		default:
-
 		}
 	}