Fix anno_barplot number placement with explicit ylim and reverse axes

[foertsch]

Reviewer note: I kept this as two separate commits on purpose so each fix can be reviewed or cherry-picked independently.

• 2bc989e is the narrower #1248 fix for explicit ylim
• f74fdda is the reverse-axis follow-up for #1247

If you'd prefer, I can also split these into two separate PRs, but I kept them together since they touch the same anno_barplot() code path and share related regression coverage.

Summary

• Respect explicit ylim when add_numbers = TRUE
• Fix reverse barplot number spacing/placement
• Add focused regression tests for both cases

Commit breakdown

1. 2bc989e Respect explicit ylim in anno_barplot with add_numbers

   • fixes Barplot options add_numbers messes with ylim #1248
   • keeps data_scale unchanged when ylim is explicitly supplied
   • reserves room for labels via annotation extension instead of stretching the axis range

2. f74fdda Fix reverse anno_barplot number spacing and labels

   • fixes Incorrect numbers on reverse barplots #1247
   • prevents reverse barplots from expanding data_scale just to fit labels
   • places label room on the correct outer side
   • uses original values for reverse label formatting

Tests

Added:

• tests/testthat/testthat-AnnotationFunction-barplot-explicit-ylim.R
• tests/testthat/testthat-AnnotationFunction-barplot-reverse.R

Verified locally with:

testthat::test_file("tests/testthat/testthat-AnnotationFunction-barplot-explicit-ylim.R")
testthat::test_file("tests/testthat/testthat-AnnotationFunction-barplot-reverse.R")
testthat::test_dir("tests/testthat", filter = "AnnotationFunction-barplot|UpSet")