chore: address stale TODO comments across codebase (#3108)

* chore: address stale TODO comments across codebase

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

* refactor: extract list marker helper and add no-pipeline test coverage

- Extract duplicated "set marker + add list item" logic in
  _add_list_item() into _add_list_item_with_marker() helper method
- Add tests for defensive "no pipeline" code path in _execute_pipeline()

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

* style: fix ruff formatting in list marker helper

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

* fix: skip bbox validation in fuzzy mode and increase tolerance

Fuzzy tests (OCR, image) have inherent coordinate variability, so bbox
checks are skipped. For non-fuzzy tests, increase tolerance from 0.01
to 0.5 to account for cross-platform numeric variance.

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

* test: use reasoned bbox tolerances in verify utils

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

* test: scale bbox tolerance by page extent

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

* test: assert bbox presence in verification

Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>

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Signed-off-by: Hassan Raza <raihassanraza10@gmail.com>
Signed-off-by: Peter W. J. Staar <91719829+PeterStaar-IBM@users.noreply.github.com>
Co-authored-by: Peter W. J. Staar <91719829+PeterStaar-IBM@users.noreply.github.com>