build: Migrate vcsc to vsparse from PyPI, add plotting dependencies, and broaden python support

[aarmey]

Summary of changes

• Replace vcsc git source with PyPI vsparse>=0.2.0
• Add hdf5plugin, matplotlib, and seaborn to project dependencies so scrise.plotting works out of the box
• Update vsparse imports in factorization and analysis scripts
• Note: Widening requires-python to >= 3.12 is blocked by upstream parafac2>=1.6.0 which currently requires Python >= 3.13 on PyPI; requires-python is retained at >= 3.13 so uv lock resolves cleanly.