Introduce configurable parameters for minimum rows and columns in table detection

[tis-abe-akira]

Description
This PR introduces two new parameters to control table detection during Markdown output:

• min_table_rows: Minimum number of rows required for a table to be included
• min_table_cols: Minimum number of columns required for a table to be included

Both parameters include basic validation to prevent invalid values.

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Motivation / Background
In the current implementation, tables with fewer than 2 rows are automatically excluded. While this works for most cases, real-world PDFs sometimes contain edge cases where a single-row table should still be recognized:

• When the last row of a table is split onto the next page
• When a separator line appears immediately after the header, resulting in only one detected row

In these situations, treating all single-row tables as invalid leads to loss of useful information. By making the minimum rows and columns configurable, users gain flexibility to adapt table detection to their specific document structures.

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Changes

• Added parameters min_table_rows and min_table_cols
• Added validation for parameter values
• Updated table filtering logic to use configurable thresholds

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Notes
This change preserves the current default behavior (min_table_rows = 2, min_table_cols = 2) to avoid breaking existing usage, while allowing users to override when needed.