docs: show model counts per task in the model zoo

[afrendeiro]

The Model Zoo page now shows, directly under each model-type heading, how many models that section lists. The counts are computed at docs build time from the installed lazyslide_models registry, so they can never drift from the rendered lists.

• docs/source/conf.py: template_model_api() emits a bold count line (**31 models**, pluralized) below each heading; the Base model class section is excluded since it lists abstract base classes, not models.
• uv.lock: bumps lazyslide-models from 0127beb to 365c7ba. The docs build resolves models from the lockfile, and the previous pin predated several models (ClassPose, Prism2, mSTAR, WaiV, RudolfV-2, STPath, GigaPath-Flash), which made the generated model lists silently stale. Split into a separate commit for reviewability.

Verified locally: uv run task doc-build succeeds and the generated models.rst shows 31 vision, 12 multimodal, 11 segmentation, 7 tile prediction, 2 feature prediction, 8 slide encoder, 9 CV features, 3 style transfer, 1 image generation.