Bump transformers from 5.3.0 to 5.12.1

Bumps [transformers](https://github.com/huggingface/transformers) from 5.3.0 to 5.12.1.
- [Release notes](https://github.com/huggingface/transformers/releases)
- [Commits](huggingface/transformers@v5.3.0...v5.12.1)

---
updated-dependencies:
- dependency-name: transformers
  dependency-version: 5.12.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -102,7 +102,7 @@ colvision = [
     # Vision-based RAG with ColVision models (ColPali, ColQwen2/2.5, ColGemma3, ColSmol)
     "mmore[api, index]",
     "colpali-engine>=0.3.16",
-    "transformers==5.3.0",  # pinned: matches the colpali adapter key layout
+    "transformers==5.12.1",  # pinned: matches the colpali adapter key layout
     "PyMuPDF",
     "accelerate>=0.30",
     "pyarrow",