fix: more lint fixes for ST1005 and QF1003

- Add space separators between concatenated error string parts
- Remove trailing punctuation from error messages
- Convert if-else chain to tagged switch in handlers_test.go

Author: DeliciousBuding

internal/client/client.go

@@ -78,17 +78,17 @@ func Connect(pipeName string, logger *log.Logger) (*Client, error) {
 			}
 			return c, nil
 		}
-		return nil, fmt.Errorf("all %d pipes failed. Last error: %w"+
-			"Try: restart Codex Desktop, then re-open the Codex Chrome Extension.",
+		return nil, fmt.Errorf("all %d pipes failed; last error: %w. "+
+			"Try: restart Codex Desktop, then re-open the Codex Chrome Extension",
 			len(pipes), lastErr)
 	}
 
 	path := discovery.PipePath(pipeName)
 	conn, err := dialNamedPipe(path)
 	if err != nil {
-		return nil, fmt.Errorf("dial pipe %s: %w"+
-			"This usually means the pipe is stale (Codex Desktop restarted) or the extension lost its host.\n"+
-			"Try: restart Codex Desktop, then re-open the Codex Chrome Extension.", path, err)
+		return nil, fmt.Errorf("dial pipe %s: %w. "+
+			"This usually means the pipe is stale (Codex Desktop restarted) or the extension lost its host. "+
+			"Try: restart Codex Desktop, then re-open the Codex Chrome Extension", path, err)
 	}
 
 	return NewFromConn(conn, logger), nil

internal/mcp/handlers_test.go

@@ -122,9 +122,10 @@ func callToolRaw(t *testing.T, s *MCPServer, name string, args map[string]interf
 func flattenContent(content []Content) string {
 	parts := make([]string, 0, len(content))
 	for _, c := range content {
-		if c.Type == "text" {
+		switch c.Type {
+		case "text":
 			parts = append(parts, c.Text)
-		} else if c.Type == "image" {
+		case "image":
 			parts = append(parts, "[image:"+c.MimeType+"]")
 		}
 	}