[Bug] Fix Malformed Table Crash

[dfop02]

Description

Problem

get_table_dimensions() was underestimating the number of columns when rowspan shifts cells into the next rows.
This caused handle_table() to access columns outside the grid, raising:

IndexError: list index out of range

Solution

Updated get_table_dimensions() to simulate real table layout using a used_cells grid, accounting for both rowspan and colspan.

Also added a small bounds check in handle_table() for extra safety.

Tests

Added a regression test for malformed tables where rowspan causes column overflow, ensuring:

• no exception is raised
• correct dimensions are created
• cells are placed in the right columns

Impact

• Fixes crashes on malformed/complex tables
• Improves accuracy of table rendering

Issue Reference

Fixes #70

Checklist Before Requesting a Review

• I have performed a self-review of my code.
• My code follows the project's coding style and guidelines.
• I have run tests and verified that all existing and new tests pass.
• I have added new tests to cover my changes.