This PR adds a new show_rows parameter to the create_dt() function to allow users to customize the default number of rows displayed in DataTable outputs, addressing a common user request for more flexible table display options.

The rounding argument also now accepts a named list, allowing more flexibility in specifying which rounding formats to use for which columns. This was achieved with backward compatibility.

Changes Made

New Parameter:

• Added show_rows parameter with default value 10 to maintain backward compatibility
• Accepts numeric values or "All" to specify the default number of rows to display
• The specified value becomes the first option in the DataTable length menu

Dynamic Length Menu Construction:

• Replaced hardcoded lengthMenu with dynamic construction based on show_rows value
• When show_rows = 25: Creates menu [25, 10, 50, -1] with labels [25, 10, 50, "All"]
• When show_rows = "All": Creates menu [-1, 25, 10, 50] with labels ["All", 25, 10, 50]
• Other numeric values are placed first in the menu with remaining standard options

Examples:

# Default behavior (unchanged)
create_dt(data)

# Show 25 rows by default
create_dt(data, show_rows = 25)

# Show all rows by default
create_dt(data, show_rows = "All")

Backward Compatibility

All existing code continues to work without modification since show_rows defaults to 10, preserving the original behavior. The change affects 11 files across the codebase that use create_dt(), all of which remain fully compatible.

Testing

Added comprehensive test suite in test-create_dt.R to verify:

• Default parameter behavior
• Numeric show_rows values
• "All" and -1 parameter values
• Proper DataTable object creation

Fixes #245.