t2s invariants: fold negated arguments and trace of a rank-1 outer product

[petlenz]

The t2s invariants don't fold a negated tensor argument or a rank-1 outer product. On main (dim 2 and 3):

Expression	Today	Expected
trace(-A)	tr(-A)	-tr(A)
norm(-A)	norm(-A)	norm(A)
det(-A)	det(-A)	det(A) for even dim, -det(A) for odd dim
dot(-A)	dot(-A)	dot(A)
trace(otimes(u, v)), u,v rank-1	tr(outer(u, {1}, v, {2}))	dot_product(u, {1}, v, {1})

Scaled arguments already fold (trace((-2)*A) → -2*tr(A)); only the bare tensor_negative node is missed. The trace(-A) and trace(u⊗v) rules existed on the old 72-trace-simplifier branch but were not part of the #70–#72 rescue (5252027).

Plan: add them as t2s_rules (try_trace_negative, try_trace_outer_product, try_norm_negative, try_det_negative, try_dot_negative) driven by the factories, with rule unit tests and end-to-end checks.

Signed-off-by: petlenz peterlenz89.pl@gmail.com