[j-emberton]

Remove support for the old Annotated[Tensor, DIM] declaration now that the quantity annotation migration is on main.

Changes

• Reject dimensioned Tensor annotations at system fields, equation parameters, transform parameters and return values, with an error pointing to the replacement API.
• Keep Annotated[Quantity, DIM] for scalar quantities, Annotated[QuantityTensor, DIM] for tensor-only quantities, and Annotated[Quantity | QuantityTensor, DIM] for pointwise quantities.
• Preserve exact Domain hints on pointwise equations, while rejecting tensor-domain requirements on scalar system fields.
• Add focused regression tests for the removed API and invalid scalar-domain declarations.

Scope

This is the final API-removal step. Previous migrations of tests, benchmarks, documentation and worked examples are already merged. No migration changes are repeated here.

Validation

• Rebases cleanly on current main as one commit, with three changed files.
• GitHub reports the PR as mergeable.
• Full CI is awaiting results on the rebased commit.