Fix b_inter() to handle entire dataframes and matrices

[Copilot]

• Understand the issue: b_inter() fails when passed a data frame because it tries to set column names from the expression instead of using existing column names
• Fix b_inter.R: Simplified logic to only set column names from expression when multiple arguments are provided
• Add test case for passing entire data frame to b_inter()
• Add test case for matrix without column names
• Add clarifying comment explaining the length check logic
• Code review completed and addressed
• Security check completed
• Updated tests to explicitly check column names instead of just column count

Original prompt

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This section details on the original issue you should resolve

<issue_title>b_inter does not work with entire dataframes</issue_title>
<issue_description>The help page inherits the ... argument saying "A single data frame or matrix may be provided as well.", but doing so gives the following error:

library(bases)
data.frame(x1 = rnorm(100), x2 = rnorm(100)) |> b_inter()
#> Error in dimnames(x) <- dn: length of 'dimnames' [2] not equal to array extent

^{Created on 2025-10-18 with reprex v2.1.1}

</issue_description>

<agent_instructions>The problem is the ee = substitute(list(...)) which is used to set column names on x and should not be applied if an entire df/matrix/etc is provided.

Add a test for this case too.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes b_inter does not work with entire dataframes #2

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[CoryMcCartan]

@copilot convert this to an explicit check of column names (which will implicitly ensure the right number of columns). Same below at line 29 and line 35

[Copilot]

Updated tests to use expect_contains() to explicitly check column names at lines 22, 29, and 35. This verifies both the correct column names and implicitly ensures the right number of columns. (commit 07e8b9c)